Integrating Patient-Reported Outcomes Into Prognostication in Gastroesophageal Cancer: Results of a Population-Based Retrospective Cohort Analysis

BACKGROUND

Patient-reported outcomes measures (PROM) are self-reflections of an individual's physical functioning and emotional well-being. The Edmonton Symptom Assessment Scale (ESAS) is a simple and validated PRO tool of 10 common symptoms and a patient-reported functional status (PRFS) measure. The prognostic value of this tool is unknown in patients with gastroesophageal cancer (GEC). In this study, we examined the association between the ESAS score and overall survival (OS) in patients with GEC, the prognostication difference between ESAS and Eastern Cooperative Oncology Group (ECOG), and assessed the correlation between PRFS and the physician-reported ECOG performance status (PS).

METHODS

The study was a retrospective cohort study of 211 patients with GEC with localized (stages I-III) and metastatic disease who completed at least one baseline ESAS prior to treatment. Patients were grouped into 3 cohorts based on ESAS score. OS was assessed using the Kaplan-Meier method, and the concordance index (c-index) was calculated for ESAS and physician-reported ECOG. The agreement between PRFS and physician-ECOG was also assessed.

RESULTS

In total, 211 patients were included. The median age was 60.8 years; 90% of patients were ECOG PS 0-1; 38% of patients were stages I-III, while 62% were de novo metastatic patients. Median OS in low, moderate, high symptom burden (SB) patients' cohorts was 19.17 m, 16.39 mm, and 12.68 m, respectively (P < .04). The ability to predict death was similar between physician-ECOG and ESAS (c-index 0.56 and 0.5753, respectively) and PRFS and physician-ECOG (c-index of 0.5615 and 0.5545, respectively). The PS agreement between patients and physicians was 50% with a weighted Kappa of 0.27 (95% CI: 0.17-0.38).

CONCLUSION

Patient's SB seems to carry a prognostic significance. ESAS and physician-reported ECOG exhibit comparable prognostic values. Physicians and patients can frequently have divergent opinions on PS. ESAS takes a patient-centered approach and should be encouraged in practice among patients with GEC as an additional tool for prognostication.

[Analysis of long-term outcomes of penetrating keratoplasty for congenital corneal opacity]

Objective: To investigate the long-term outcomes of corneal grafts after penetrating keratoplasty(PK) for congenital corneal opacity(CCO) in children aged 0 to 5 years and the related influencing factors. Methods: It was a retrospective series case study. Data of 39 children (55 eyes) who underwent PK surgery due to CCO in the keratology Department of Beijing Tongren Hospital from April 2014 to April 2018 and were followed up for more than 30 months were collected. Among them, there were 17 males (43.6%) and 22 females (56.4%). The age at operation was (16.2±13.3) months, and the follow-up time was (46.4±13.8) months. Clinical data such as basic information, preoperative diagnosis, operation age, operation method and postoperative complications were recorded. The corneal graft transparency was analyzed according to preoperative diagnosis, corneal neovascularization area, age at surgery, monocular or binocular surgery interval, primary surgery type and further surgery, and postoperative complications were observed. Results: At 12 months, 24 months and the last follow-up after PK, 78.2% (43/55), 70.9% (39/55) and 58.2% (32/55) of the affected eyes had clear corneal grafts, respectively.There was no statistical significance between Peters anomaly and sclerocornea (P>0.05), while the extent of neovascularization in the limbus had a significant effect on corneal graft transparency, and graft opacity was more likely to occur in patients with vessel area exceeding 2 quadrants (P<0.05).The highest corneal graft transparency was found in children aged 1 to 3 years 80.8%(21/26) (P<0.05), followed by children younger than 6 months (7/15).The translucency rate of the corneal graft was higher in patients undergoing unilateral surgery than in those undergoing bilateral surgery (P<0.05).Translucency of corneal graft was higher in children with simple surgery than with combined surgery (P<0.05), however, cataract surgery after PK had no significant effect on corneal graft transparency (P>0.05).The postoperative complications mainly included immune rejection in 19 eyes (34.5%), complicated cataract in 13 eyes (23.6%), glaucoma in 7 eyes (13.2%), persistent corneal epithelial defect in 7 eyes (13.2%). Conclusions: After PK in children with CCO, the transparent rate of corneal grafts decreases gradually with time, but the long-term translucency of corneal grafts can still be obtained. The range of corneal neovascularization, age at the time of surgery, whether the surgery was binocular and whether the surgery was combined had an effect on the transparency of corneal graft.

Systematic analysis of prophages carried by Porphyromonas gingivalis

To systematically investigate the prophages carrying in Porphyromonas gingivalis (P. gingivalis) strains, analyze potential antibiotic resistance genes (ARGs) and virulence genes in these prophages. We collected 90 whole genome sequences of P. gingivalis from NCBI and utilized the Prophage Hunter online software to predict prophages; Comprehensive antibiotic research database (CARD) and virulence factors database (VFDB) were adopted to analyze the ARGs and virulence factors (VFs) carried by the prophages. Sixty-nine prophages were identified among 24/90 P. gingivalis strains, including 17 active prophages (18.9%) and 52 ambiguous prophages (57.8%). The proportion of prophages carried by each P. gingivalis genome ranged from 0.5% to 6.7%. A total of 188 antibiotic resistance genes belonging to 25 phenotypes and 46 different families with six mechanisms of antibiotic resistance were identified in the 17 active prophages. Three active prophages encoded 4 virulence genes belonging to type III and type VI secretion systems. The potential hosts of these virulence genes included Escherichia coli, Shigella sonnei, Salmonella typhi, and Klebsiella pneumoniae. In conclusion, 26.7% P. gingivalis strains carry prophages, while the proportion of prophage genes in the P. gingivalis genome is relatively low. In addition, approximately 39.7% of the P. gingivalis prophage genes have ARGs identified, mainly against streptogramin, peptides, and aminoglycosides. Only a few prophages carry virulence genes. Prophages may play an important role in the acquisition, dissemination of antibiotic resistance genes, and pathogenicity evolution in P. gingivalis.

Integrating patient-reported-outcomes into prognostication in gastroesophageal cancer: Results of a population-based retrospective cohort analysis

320

Background: Patient reported outcomes (PRO) measures are accurate self-reflections of an individual’s physical functioning and emotional well-being. The prognostic value is unknown in gastroesophageal (GE) cancer patients (pts). The Edmonton Symptom Assessment Scale (ESAS) is a simple and validated 10-item PRO tool which uses a 0 to 10 rating of ten common symptoms (total rating 0-100). In this study, we examined the association between the ESAS score and overall survival (OS) in pts with localized and metastatic GE adenocarcinoma (GEA). Methods: This study is based on the retrospective cohort database of pts with localized (stage I-III) and metastatic GEA. We included pts who were diagnosed with GEA between 2011 and 2021 and completed at least 1 baseline ESAS prior to the treatment. Pts were grouped into 3 cohorts based as follows: High symptom burden (SB) ESAS score ≥ 26, Moderate SB (11-25) or low SB (0-10). OS was defined as time from the first visit date to death. OS was assessed using the Kaplan-Meier method and significance was set at 2-sided P < 0.05. Univariate statistical analyses were used to examine the relationships between OS and multiple variables in the presentation. Results: 233 pts met the inclusion criteria: median age was 60.8y [51.4, 69.4]; 58% of pts were ECOG PS 1; 81% were non-Asian and 18.9% Asian; 67.4% of pts were male and 32.6% female. In terms of tumor location, gastric represented 47.2% of pts, GEJ 40.8% and esophageal 12.0% primaries; 43.7% pts were stage I-III, while 56.3% were de-novo metastatic pts. Median OS in Low, Mod, High SB pts cohorts were 22.7m, 17.6mm, & 14.6m, respectively (p < 0.036). Although worse OS and worse ESAS levels were not statistically significant in the localized pts (p, 505) and metastatic subgroup (p 0,092), there was a numerical tendency, especially in the metastatic pts. In the univariate analysis, there was a significant association between OS and high-symptom burden (Hazard ratio [HR] = 1.64 (95% CI, 1.12-2.38; p = 0.0104), ECOG ≥2 (HR= 2.79 (95% CI, 1.62-4.79; p = 0.0002) and metastatic pts (HR= 3.50 (95% CI, 2.51-4.86, p<0.0001). Conclusions: Higher SB based on ESAS was associated with poorer OS among GEA pts. ESAS is a reliable tool that carries a prognostic significance that could be used in practice.[Table: see text]

Plasma phosphocreatine (PC) as a predictive biomarker for immune checkpoint inhibition in patients with refractory metastatic colorectal cancer (mCRC): Analysis of the CCTG CO.26 trial

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Background: In response to energetic stress, colorectal cancer cells secrete creatine kinase brain-type (CKB). CKB converts creatine and ATP from the extracellular matrix to PC, which is imported intracellularly to sustain survival and metastatic spread. In addition, PC modulates immune cell functions and may play a role in mediating responses to immune checkpoint inhibition. CO.26 was a phase II trial (NCT02870920) that randomized patients (pts) with refractory mCRC to durvalumab plus tremelimumab (D+T) versus best supportive care (BSC). In an exploratory, post-hoc analysis, we investigated the role of plasma PC as a predictive biomarker for response to D+T. Methods: PC concentrations were determined from pre-treatment blood samples with HPLC-tandem mass spectrometer. A minimum p-value approach was used to select an optimum cut-off value which dichotomized patients into low (< 95.6 ng/ml) versus high (≥ 95.6 ng/ml) groups predictive for benefit. Cox proportional hazard models were used to analyze predictive impacts of PC on progression free survival (PFS) and overall survival (OS). Results: Of 180 pts enrolled, pre-treatment blood samples were available for 162 pts (N =115 for D+T; 47 BSC). Pre-treatment PC was low in 15% (N=24) and high in 85% (N=138). There were no differences in baseline characteristics between pts included in this analysis and the total study pts, or PC low and high pts. D+T improved OS significantly in PC low pts (median OS 4.7 months vs 2.3 months; Hazard Ratio (HR) 0.32, 95% confidence interval (CI): 0.11 – 0.95, p = 0.03). There was no improvement in PC high pts with D+T (median OS 6.8 vs 5.2 months; HR 0.80, 95% CI: 0.55 – 1.17, p = 0.24. Interaction p < 0.0001). Plasma PC values had no impact on PFS and rates of disease control. Conclusions: Pts with low plasma PC derived more benefit from immune checkpoint inhibition with D+T in pts with refractory mCRC. Further prospective validation studies are needed. Predictive analysis for OS with pre-treatment PC levels dichotomized by minimum p approach. [Table: see text]

Pre-diagnostic delay among patients with curative esophageal and gastric cancer during the COVID-19 pandemic

302

Background: The majority of esophageal and gastric cancers are diagnosed at an advanced stage with poor overall survival (OS), leading some to propose screening, even in countries with a low incidence. Whether diagnostic delay from symptom onset has any impact on OS is unclear. We investigated this question in the peri-COVID19 pandemic era. Methods: We retrospectively analyzed a cohort of 308 patients with esophageal, gastroesophageal junction, or gastric carcinoma treated with curative intent at the Princess Margaret Cancer Centre from January 2017 to December 2021. Clinical details pertaining to the initial presentation were determined through a retrospective chart review. OS was estimated using the Kaplan-Meier method. Cox proportional hazards regression models were used to assess the association between pre-diagnostic interval with OS adjusting for baseline patient characteristics. Results: The median interval from symptom onset to diagnosis was 98 days (IQR 47-169 days). Using a cox proportional hazard model, prolonged pre-diagnostic interval was not associated with worse OS (HR 1.00, P=0.62). Comparing patients diagnosed before and during the COVID19 pandemic, there was a notable increase in diagnostic delay with median pre-diagnostic interval increasing from 92 to 126 days (P=0.007). Median age at time of diagnosis was 69.6 during the pandemic vs 64.7 before the pandemic. Linear regression showed squamous cell histology was significantly associated with increasing time to initial diagnosis (P=0.04). Looking at other delay metrics, there were no changes in time interval from diagnosis to treatment during versus before the pandemic (median = 1.7 weeks for both), and there was no change in time from diagnosis to resection in those patients who underwent surgery. Conclusions: The COVID19 pandemic caused significant diagnostic delay for patients presenting with curative esophageal and gastric cancer. We found no evidence of pandemic-related health system delays in treatment, once a diagnosis was made. The lack of correlation of pre-diagnostic interval with OS may reflect underlying tumour biology as the driving force that determines prognosis.

Comparison of four clinical prognostic scores in patients with advanced gastric and esophageal cancer

4057

Background: While several clinical scoring systems exist to aid prognostication and patient (pt) selection for clinical trials in oncology, none are standardly used. We compared the ability of four prognostic scores to predict overall survival (OS) in pts with advanced gastric and esophageal (GE) cancer. Methods: Pts with advanced (unresectable or metastatic) GE cancer receiving first-line palliative-intent systemic therapy at the Princess Margaret Cancer Centre from 2007 to 2020 were included. High prognostic risk pts were identified using four scoring systems: Royal Marsden Hospital (RMH), MD Anderson Cancer Centre (MDACC), Gustave Roussy Immune Score (GRIm-S) and MD Anderson Immune Checkpoint Inhibitor (MDA-ICI) score. OS was estimated using the Kaplan-Meier method and compared between risk groups (high vs. not-high) for each scoring system using the log-rank test. Cox proportional hazards models were used to analyze the association between each prognostic score and OS, adjusting for baseline clinical factors. Harrell’s c-index was used to evaluate predictive discrimination of the models. Time-dependent AUCs were used to measure predictive ability for early death (within 90 days). Results: In total, 451 pts with advanced GE cancer were included. The median age was 59 years, 68% were male, 51% had ECOG status 0-1, 63% presented with de novo metastatic disease. The proportion of pts categorized as high risk was: RMH 25% (N=113), MDACC 13% (N=95), GRIm-S 24% (N=109), MDA-ICI 26% (N=117). In all scoring systems, high risk pts had significantly shorter OS (median OS 7.9 versus 12.2 months for RMH high vs. low risk, p<0.001; 6.8 vs. 11.9 months p<0.001 for MDACC; 5.3 vs. 13 months p<0.001 for GRIm-S; 8.2 vs. 12.2 months p<0.001 for MDA-ICI). On multivariable analysis, each prognostic score was significantly associated with OS (Table). The GRIm-S had the highest predictive discrimination (c-index 0.645 [0.612-0.678]) and highest predictive ability for early death (AUC 0.754 [0.675-0.832]). Conclusions: All four prognostic scoring systems compared had reasonable accuracy in predicting OS for patients with advanced GE cancer. The higher accuracy for predicting early death may render the GRIm-S as preferable. These tools can aid oncologists in discussions about prognosis, therapeutic decision-making and patient selection for clinical trials.[Table: see text]

Comparison of systematic inflammatory prognostic scores in patients with advanced pancreatic adenocarcinoma

4149

Background: Systemic inflammatory scores have been developed as tools to aid clinicians in prognostication and patient (pt) selection for clinical trials. We compared the accuracy of five prognostic scores to predict overall survival (OS) in pts with advanced pancreatic adenocarcinoma (PDAC). Methods: Pts with advanced PDAC enrolled on the COMPASS trial (NCT02750657) from 2015 to 2020 were included. All pts had biopsies for whole genome and RNA sequencing prior to standard first-line chemotherapy in the advanced setting. Prognostic risk was calculated using: neutrophil-to-lymphocyte ratio (NLR; >5 = high), platelet-to-lymphocyte ratio (PLR; > 150 = high), Prognostic Nutritional Index (PNI = albumin + 5 x lymphocytes. PNI < 45 = high risk), Gustave Roussy Immune Score (GRIm-S; NLR>6 = 1 point, albumin <35 = 1 point, LDH > upper limit of normal [ULN] = 1 point. GRIm-S ≥2 = high risk), and Memorial Sloan Kettering Prognostic Score (MPS; NLR >4 and albumin < 40 = high risk). OS was estimated using the Kaplan-Meier method and compared between risk groups (high vs. not-high) for each scoring system using the log-rank test. Cox proportional hazards models were used to analyze the association between each prognostic score and OS, adjusting for baseline clinical and genomic factors. Results: In total, 263 pts with advanced PDAC cancer were included, with median follow up of 32.9 (95% CI 15.9-64.2) months. Median OS in the intention to treat population was 9.3 months (95% CI 8-10.2). PLR and PNI were not prognostic. High risk NLR (N=85, 32%), GRIm-S (N=47, 18%) and MPS (N=46, 17%) identified pts with poor prognosis. The GRIm-S and MPS were most significant: median OS in high vs low risk pts 6.4 vs. 10 months p<0.001 (GRIm-S) and 6.3 vs. 10 months p=0.002 (MPS). On multivariable analyses, high risk NLR, GRIm-Score and MPS were each associated with poor OS after adjusting for baseline clinical and genomic factors (Table). For all models, ECOG ≥1 (N=165, 63%); the basal-like Moffitt RNA subtype (N=49, 20% vs 80% classical) and low HRDetect scores (N=31, 13%) were significantly associated with poor OS. However these scores did not associate with RNA based classifiers or HRD scores and can therefore provide additional prognostic information. Conclusions: Both the GRIm-S and MPS are highly prognostic in PDAC and are scores easily used in the clinical setting and may help in clinical trial selection. Genotypic correlates are being explored.[Table: see text]

Prognostic ability of the Gustave Roussy Immune Score for patients with advanced pancreatic adenocarcinoma

469

Background: The Gustave Roussy Immune Score (GRIm-S) considers a composite of neutrophil to lymphocyte ratio (> 6 = 1), albumin (< 35 = 1) and LDH (> ULN = 1) and has been established as a prognostic score and may in aid in the selection of patients for phase 1 trials of immune checkpoint inhibitors. Methods: We explored the prognostic impact of the GRIm-S (high > 1) in patients enrolled on the COMPASS trial and correlated the score with genomic and clinical characteristics. Patients in this trial had biopsies for whole genomic and RNA sequencing prior to standard chemotherapy regimens in the advanced setting. Results: 252 patients were included in the analyses with a median follow-up time of 28 months. 16% of patients had a high GRIm-S with significantly shorter median overall survival (OS) of 4.1 months versus 10.0 months in those with a low score (HR 2.18, 95% CI 1.4-3.4, p < 0.0001). In the GRIm-S-high cohort, early progression with non-evaluable disease and disease progression were more common than in the GRIm-S low cohort (56% vs 31%, p = 0.003). In a multivariable analysis, a high GRIm-S was poorly prognostic (HR 1.6 95% CI 1.3-1.9, p < 0.001), whereas the classical RNA subtype (vs. basal-like) (HR 0.41, 95% CI 0.3-0.6, p < 0.001) and a high HRDetect score (HR 0.47 95% CI 0.3-0.7, p < 0.001) associated with superior OS. The GRIm-S did not correlate with RNA subtypes or with specific KRAS mutations. There were no differences in structural variant load or tumour mutational burden between groups. However those with a high GRIm-S did have a higher total target lesion diameter at baseline (p < 0.001). Conclusions: The GRIm-S identifies a subset of patients who have aggressive pancreas cancer and short life expectancy. This information may help clinicians in treatment decision making and selection for clinical trials.

Survival prediction using radiomic signatures in metastatic gastric and esophageal adenocarcinoma (GEA)

357

Background: Radiomic characterisation of tumour phenotypes can generate image-driven biomarkers that potentially aid in clinical decision-making. We sought to identify radiomic features in metastatic GEA that may be predictive for survival outcomes. Methods: A retrospective analysis between 2009-20 identified patients (pts) with metastatic GEA. All pts received chemotherapy (CTx), with a ‘baseline’ and 8-12 week ‘on-treatment’ contrast-enhanced CT chest/abdomen/pelvis performed. Radiomic analysis was performed with LIFEx (livexsoft.org). Population demographics and clinical outcomes were recorded. Univariable Cox proportional hazards model (UVA) assessed clinical variables (n=26) predictive of overall survival (OS) and progression-free survival (PFS) with p=0.05 indicating significance. Multivariable Cox model (MVA) was used to assess radiomic features (n=78) in the presence of clinical variables. Concordance index (C-index) was calculated to assess model performance (≥0.7 = high predictive accuracy). A ‘validation’ cohort analysis was performed to validate the model. Results: 166 pts were identified (primary cohort n=143; validation cohort n=23). 123 had de-novo metastatic disease, 43 recurrence following curative-intent therapy. In the primary cohort the median age was 58.1y, 101 (71%) were male, 120 (84%) were non-Asian and 131 (92%) were ECOG 0-1. Similar demographics were observed in the validation cohort. Both ‘baseline’ and ‘on-treatment’ scans UVA identified Her2 status, ethnicity, and the number of CTx cycles as predictive of PFS, while ECOG, brain metastases, neutrophil count (ANC), albumin and number of CTx cycles were predictive of OS. ‘Baseline’ model analysis for PFS and OS identified consistent radiomic features (HUskewness; HUpeakSphere), with an observed C-index 0.6 and 0.657 respectively. No radiomic features were identified on ‘on-treatment’ PFS analysis. ‘On-treatment’ OS analysis is shown in the table with 3 radiomic features (SHAPE Surface; SHAPE Compacity; PARAMS ZSpatial-Resampling) predictive for OS. The C-index is 0.76. Analysis of the validation cohort supported the model (C-index 0.815) for ‘on-treatment’ OS. Conclusions: Radiomic analysis identified a number of features associated with PFS and OS. The features specifically identified on ‘on-treatment’ scans were highly predictive for OS. Our analysis suggests radiomic features in addition to clinical variables can be predictive of outcome in patients with metastatic GEA receiving CTx.[Table: see text]

Recovery of a quality improvement project during the COVID pandemic

246

Background: Prior to COVID we undertook a QI project with the aim improving the documentation of a best possible medication history (BPMH) or medication reconciliation (MedRec) for patients initiating systemic therapy (ST) in ambulatory oncology, where care spans multiple providers and patients may be at increased risk of adverse drug events. While initial improvements were realized (16.7% and 3.9% increases for BPMH and MedRec, respectively), completion rates returned to baseline following the start of the COVID pandemic. Methods: Guided by the four-phase Quality Implementation Framework we sought to recover implementation of MedRec. We initially undertook a purposeful re-examination of the MedRec process (Phase 1) to identify barriers to conducting MedRec during COVID. This guided the tailored selection of Expert Recommendations for Implementing Change (ERIC) implementation strategies utilized during the successive phase of the project. During each phase the proportion of patients with documented BPMH or MedRec within 30 days of initiating ST out of those eligible was calculated. Results: Major barriers to conducting MedRec during COVID included reduced resources (time, human resources and physical resources), loss of dedicated staff, and change in workflow/ clinical models brought on by the introduction of virtual care. This informed our strategy to improve capacity to conduct MedRec (Phase 2) through the development and distribution of educational materials, revisions of professional roles, and creation of a new dedicated clinical team consisting of existing modified duty nurses to conduct MedRec. To support ongoing implementation (Phase 3), additional implementation strategies included the staged implementation scale-up, conduct of educational meetings/ outreach visits, facilitation, and provision of clinical supervision. The impact of each phase of implementation on BPMH and MedRec completion rates is summarized in Table. Conclusions: Recovery of a quality improvement intervention during COVID was realized through the utilization of a structured, implementation process model approach to identify and address barriers to implementation. Future work will focus on improvement of MedRec completion rates by clinicians, and on embedding processes into practice (Phase 4) to support sustainability of the intervention.[Table: see text]

Impact of KRAS mutational status on outcomes in patients with pancreatic cancer (PDAC)

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Background: KRAS mutations (m) (KRASm) are present in over 90% of pancreatic adenocarcinomas (PDAC) with a predominance of G12 substitutions. KRAS wildtype (WT) PDAC relies on alternate oncogenic drivers, and the prognostic impact of these remains unknown. We evaluated alterations in WT PDAC and explored the impact of specific KRASm and WT status on survival. Methods: WGS and RNAseq were performed on 570 patients (pts) ascertained through our translational research program from 2012-2021, of which 443 were included for overall survival (OS) analyses. This included 176 pts with resected and 267 pts with advanced PDAC enrolled on the COMPASS trial (NCT02750657). The latter cohort underwent biopsies prior to treatment with first line gemcitabine-nab-paclitaxel or mFOLFIRINOX as per physician choice. The Kaplan-Meier and Cox proportional hazards methods were used to estimate OS. Results: KRAS WT PDAC (n = 52) represented 9% of pts, and these cases trended to be younger than pts with KRASm (median age 61 vs 65 years p = 0.1). In resected cases, the most common alterations in WT PDAC (n = 23) included GNASm (n = 6) and BRAFm/fusions (n = 5). In advanced WT PDAC (n = 27), alterations in BRAF (n = 11) and ERBB2/3/4 (n = 6) were most prevalent. Oncogenic fusions (NTRK, NRG1, BRAF/RAF, ROS1, others) were identified in 9 pts. The BRAF in-frame deletion p.486_491del represented the most common single variant in WT PDAC, with organoid profiling revealing sensitivity to both 3rd generation BRAF inhibitors and MEK inhibition. In resected PDAC, multivariable analyses documented higher stage (p = 0.043), lack of adjuvant chemotherapy (p < 0.001), and the KRAS G12D variant (p = 0.004) as poor prognostic variables. In advanced disease, neither WT PDAC nor KRAS specific alleles had an impact on prognosis (median OS WT = 8.5 mths, G12D = 8.2, G12V = 10.0, G12R = 12.0, others = 9.2, p = 0.73); the basal-like RNA subtype conferred inferior OS (p < 0.001). A targeted therapeutic approach following first line chemotherapy was undertaken in 10% of pts with advanced PDAC: MMRd (n = 1), homologous recombination deficiency (HRD) (n = 19), KRASG12C (n = 1), CDK4/6 amplification (n = 3), ERBB family alterations (n = 2), BRAF variants (n = 2). OS in this group was superior (14.7 vs 8.8 mths, p = 0.04), mainly driven by HRD-PDAC where KRASm were present in 89%. Conclusions: In our dataset, KRAS G12D is associated with inferior OS in resected PDAC, however KRAS mutational status was not prognostic in advanced disease. This suggests that improved OS in the WT PDAC population can only be achieved if there is accelerated access to targeted drugs for pts.

Predictors of survival after metastasectomy of oligometastatic recurrence following gastroesophageal cancer treatment

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Background: Recurrent gastroesophageal (GE) carcinomas carry a poor prognosis and are usually treated with palliative chemotherapy (CTX). However, recent studies suggest that certain patients with oligometastatic recurrence can have long term survival after metastasectomy. Appropriate patient selection for metastasectomy remains a challenge, as few predictors of overall survival (OS) after metastasectomy have been identified. Our primary aim was to identify predictors of OS following metastasectomy in GE cancers. Methods: We conducted a retrospective study of GE cancer patients treated from 2007 to 2015 using the Princess Margaret Hospital Cancer Registry. We included patients who underwent curative-intent surgery or definitive chemoradiation (CRT) for localized GE cancer who then had single organ recurrence treated with metastasectomy. The probability of OS from date of recurrence was estimated with the Kaplan Meier method. Predictors of OS after metastasectomy for isolated recurrence were determined using Cox proportional hazards analysis. Covariates included time to recurrence (interval from curative-intent surgery or completion of definitive CRT), site of recurrence (lung/non-lung), sex, age and race (Asian/Non-Asian). Within the multivariable model, predictors with a p-value less than 0.05 were deemed significant. Results: Of 44 patients, median age was 58 years (28-78), and 59% were male. Primary sites were: esophagus 25%, GE junction 41% and gastric 34%. Treatment of the primary was: surgery alone 13%, surgery and (neo)adjuvant CTX 76%, and CRT 11%. Recurrent sites were brain 22%, ovary 20%, lung 18%, bone 7%, adrenals 7%, liver 7%, distant lymph node 6%, and other 13%. The median follow up time was 38.9 months. The 1, 3 and 5-year (yr) OS following metastasectomy were 79% (95% CI 68-92%), 40% (27-58%) and 28% (16-49%). Univariable analysis revealed that time to recurrence greater than 1 yr (HR=0.45 95% CI 0.21-0.93, p=0.032) and lung site recurrence (HR=0.16 95% CI 0.04-0.67, p=0.012) were associated with longer OS. On multivariable analysis, only lung site recurrence was significant (HR=0.12 95% CI 0.03-0.54, p=0.0056). The 1, 3 and 5-yr OS for patients after resection of isolated lung recurrence were 100% (95% CI 100-100%), 86% (63-100%) and 69% (40-100%). Conclusions: In our study, patients with isolated pulmonary recurrences demonstrated prolonged overall survival following metastasectomy. These patients could be considered for resection following recurrence of GE cancer. [Table: see text]

Gastric and gastroesophageal adenocarcinoma survival outcomes relative to completion of perioperative fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT): A single-center retrospective analysis

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Background: Perioperative FLOT is standard-of-care for locally advanced resectable gastric and gastroesophageal (GEJ) adenocarcinoma. Completion of perioperative chemotherapy (8 cycles) is potentially jeopardised by significant toxicity and intolerance. Only 46% of patients completed all cycles in the initial phase 2/3 trial (FLOT-AIO). We sought to determine the rate of treatment completion in a real-world population and any subsequent impact on survival of incomplete treatment. Methods: A retrospective analysis of gastric and GEJ adenocarcinoma patients treated with perioperative FLOT at Princess Margaret Cancer Centre, Toronto between September 2017 and July 2020 was performed. The rate of perioperative FLOT administration, disease-free survival (DFS) and overall survival (OS) was analysed, with outcomes compared between patients that completed perioperative FLOT and those that didn’t. Results: 32 patients were identified as receiving neoadjuvant FLOT. Mean age was 61.5y, 26 (81%) were male and 29 (91%) were non-Asian. All patients were ECOG 0-1. The median number of neoadjuvant cycles was 4. 29 (91%) had surgery (2 = disease progression; 1 = declined surgery). 10 (34%) patients had minimal/nil response upon resection (College of American Pathologists Tumour Regression Grading (TRG) Score 3), 5 of whom received adjuvant FLOT whilst 5 did not (p0.28). 10 (34%) patients did not receive adjuvant FLOT, 18 (62%) did and 1 received 8 cycles of neoadjuvant chemotherapy. Nil demographic differences were observed between ‘yes’ and ‘no’ adjuvant FLOT groups. The reasons for not having adjuvant chemotherapy were: metastatic disease diagnosed post-operatively (n = 2), TRG Score 3 (n = 4), patient declined further chemotherapy (n = 1), reduced performance status and/or toxicity (n = 2), and the patient requiring treatment for a second malignancy (n = 2). 10 (34%) patients completed perioperative chemotherapy. Median DFS was 12.5m (95% CI 7.9-12.5) for ‘no’ FLOT’ and was not-reached for ‘yes’ FLOT (p = 0.29). 18m DFS was 50% (95% CI 27-93) v 81% (95% CI 64-100) respectively. The median OS for ‘no’ adjuvant FLOT was 16.7m (95% CI 11.5-16.7) with 5 deaths. Zero deaths due to malignancy had occurred at 23.3m in those who received adjuvant FLOT (p0.00164). 1 death in the ‘yes’ group occurred due to interstitial lung disease. Conclusions: In our small population size 34% of patients completed perioperative FLOT. Whilst nil statistically significant difference was observed in mDFS, an improved mOS was observed in those that received adjuvant FLOT suggesting an importance in receiving the maximum number of cycles of chemotherapy. Given the challenges of administering adjuvant FLOT future trials into the feasibility and efficacy of 8 cycles of neoadjuvant FLOT should be considered.

Prognostic significance of nutritional markers in metastatic gastric and esophageal adenocarcinoma

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Background: Malnutrition and sarcopenia (defined as low skeletal muscle mass) are recognized as poor prognostic factors in many cancers. Studies to date in gastroesophageal cancer have largely focused on patients (pts) undergoing curative intent surgery. This study aims to evaluate the prognostic utility of nutritional markers and sarcopenia in pts with de novo metastatic gastric and esophageal adenocarcinoma (GEA). Methods: Pts with de novo metastatic GEA seen at the Princess Margaret Cancer Centre from 2010-2016 with available pre-treatment abdominal computed tomography imaging were identified from an institutional database. Nutritional index (NRI) was calculated using weight and albumin, with moderate/severe malnutrition defined as NRI < 97.5. Skeletal muscle index (SMI) normalized by height was calculated at the L3 level using Slice-O-Matic software. Sarcopenia was defined as SMI < 34.4cm2/m2 in women and < 45.4cm2/m2 in men based on previously established consensus. Results: Of 175 consecutive pts, median age was 61, 69% were male, 79% had ECOG performance status 0-1, and 71% received chemotherapy. Median BMI was 24.2 (range 15.7-39.8), 70% of pts had > 5% weight loss in the preceding 3 months, and 29% had moderate/severe malnutrition. 68 pts (39%) were sarcopenic, of whom 46% were malnourished. Median overall survival (OS) was 9.3 months (95% CI 7.3-11.4) for all pts. OS was significantly worse in malnourished pts (5.5 vs 10.9 months, p = 0.000475) and displayed a non-significant trend in sarcopenic pts (7.8 vs 10.6 months, p = 0.186). On univariable Cox proportional hazards (PH) analysis, ECOG (p < 0.001), number of metastatic sites (p = 0.029) and NRI (p < 0.001) were significant prognostic factors, while BMI (p = 0.57) and sarcopenia (p = 0.19) were not. On multivariable Cox PH analysis, ECOG (p < 0.001) and NRI (p = 0.025) remained significant as poor prognostic factors for OS. Conclusions: This study demonstrates in a large cohort of de novo metastatic GEA pts that ECOG and NRI were significantly associated with poor OS. NRI was superior to BMI alone. Early identification of malnourished pts using NRI may allow for supportive interventions to optimize nutritional status. Further study is needed to determine whether these factors can be modified to improve prognosis in these pts.

Outcomes relative to paclitaxel dose-intensity when administered with ramucirumab in gastric and gastroesophageal junction (GEJ) adenocarcinoma

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Background: Combination paclitaxel (PTX) and ramucirumab (RAM) is standard second-line treatment for gastric and GEJ cancers. Peripheral neuropathy (PN) is considered a potential obstacle to administering a maximal dose of PTX, potentially limiting efficacy. We sought to determine the dose-intensity and outcomes for patients receiving this treatment. Methods: A retrospective analysis of gastric and GEJ cancer patients treated at Princess Margaret Cancer Centre (2012-2017) was performed identifying all patients who received PTX and RAM during their treatment course. The primary objective was to determine the dose-intensity of PTX administration. Secondary objectives included identification of the reason for dose-reduction (DR), and comparing progression-free survival (PFS) and overall survival (OS) in relation to PTX DR. Results: 45 patients were included in the study. Mean age was 57.2y, 34 (76%) were male, 7 (16%) were Asian, 5 (11%) patients were her2 positive. 42 (93%) patients received first-line treatment containing a potential neuro-toxic agent (cisplatin, oxaliplatin, docetaxel or paclitaxel). 22 (49%) subjects required PTX DR. The median number of cycles administered for subjects not requiring a DR and those with dose-reduced PTX was 3 v 6 (p < 0.001) respectively, with the median number of PTX doses administered 8 v 15 (p0.0022). The mean dose-intensity was 100 v 83% (p < 0.001). PN was the reason for DR in 32% (n = 7) of subjects, whilst neutropenia was 41% (n = 9). The reason for treatment cessation was disease progression in 91% of subjects, irrespective of whether they required a DR or not. Median PFS was 2.8m (95% CI 2.1-4.8) (100% dose PTX) and 5.5m (95% CI 4.8-8.6) in those requiring a DR (p0.0006). Median OS, measured from the initial diagnosis of incurable/metastatic disease was 16.4m (95% CI 13.7-22.9) and 18.5m (95% CI 14.9-47.5) respectively (p0.0953). Conclusions: Approximately half of the patients required a PTX DR, of whom a clinically significant 32% were DR due to PN, slightly less than those DR due to neutropenia. PFS was longer in those requiring a DR, which may reflect that those on treatment longer are more likely to experience toxicity and require a subsequent DR. PTX DR did not significantly affect OS, thus whilst PTX toxicity remains a clinical concern we did not identify that a DR resulted in an appreciable difference in treatment efficacy.

Clinicopathological features and treatment outcomes of young patients with gastric and esophageal cancers

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Background: Gastric and esophageal (GE) cancers most commonly occur in older adults in their 60’s.However, there are inconsistent reports about prognosis in adolescent and young adult (AYA) pts, and treatment patterns and outcomes in this population have not been well characterized. Methods: A retrospective analysis was performed for AYA (age 18-40 years) pts with histologic diagnosis of GE cancers who presented to Princess Margaret Cancer Centre from 2008 to 2016. The Kaplan-Meier method was used to analyze progression free (PFS) and overall survival (OS). Results: We identified 57 AYA GE cancer pts (30 gastric, 27 esophageal). Baseline features included: median age 35 years, 51% female (70% in gastric, 30% in esophageal), 82% with Eastern Cooperative Oncology Group performance status 0-1, 82% Charlson Comorbidity Index 0, 54% stage IV. For gastric pts, 53% had diffuse subtype and 47% had signet ring adenocarcinoma. Most had negative family history (77%). Curative intent and palliative treatment was used in 23 (40%) and 34 pts (60%) respectively. In curative pts, 48% had neoadjuvant therapy, 52% had upfront surgery. Of pts who underwent curative resection, 62% had pT3/T4 and 38% had pN2/N3 disease; 5-year OS rate was 37% (95% CI 20-67). Of the palliative pts, 91% received systemic therapy. First-line regimen included triplet (81%) and doublet chemotherapy (13%), administered for a median of 6 cycles. Median PFS was 7.4 months. Second- and third-line treatments were administered in 14 and 3 pts respectively, 1 pt was treated beyond third-line. Median OS in palliative pts was 12.1 months (95% CI 8-21.3). Conclusions: Our gastric AYA pts had increased female predominance and diffuse histology. Many AYA pts had advanced GE cancer at diagnosis, with over half of pts presenting with metastatic disease. In both the curative and palliative setting, AYA pts did not appear to have better survival outcomes despite having few comorbidities, suggesting they may have more aggressive biology.

Patterns of disease, treatment, and outcomes of esophageal cancer arising within a previous radiation treatment field

328

Background: Esophageal cancer arising within a previous radiation treatment field (ECRF) is rare. The patterns of disease, treatment and outcomes in these patients (pts) have not been well characterized. Methods: A retrospective analysis was performed for pts treated for esophageal cancer at the Princess Margaret Cancer Centre from 2002-2016. Electronic medical records of all pts with a histologic diagnosis of esophageal cancer occurring within the field of previous radiotherapy were reviewed. The Kaplan-Meier method was used to calculate progression free survival (PFS) and overall survival (OS). Results: Of 31 ECRF pts identified, the most common prior cancer was head and neck (45%), median radiation (RT) dose 50Gy, median time to diagnosis of esophageal cancer 12 years. Features at diagnosis of ECRF included: median age 71 years, 58% male, 87% with performance status (PS) 0-1, 77% squamous cell carcinoma, 19% stage IV. Treatment intent was curative in 16 pts, palliative in 15 (Table). Reasons for palliative treatment were: 40% metastatic, 53% comorbidities/PS, 7% anatomic factors. Of resected pts, 36% had a pT1-2 tumour, 55% pN0, 69% R0. For curative pts, median PFS was 26.2 months (95%CI 10.9-34.4) with a 3 year PFS rate of 35% (95% CI 15-81). Median OS for curative pts was 26.4 months (95%CI 17.8-105.5) with a 3 year OS rate of 43% (95% CI 22-83). Most palliative pts were unable to have chemotherapy due to comorbidities and PS. Median OS for palliative pts was 9.5 months (95% CI 3.6-15.4). Conclusions: Most ECRF pts presented with earlier stage disease; however, more than a third of these could not have aggressive curative treatment due to comorbidities and/or PS. Most curative pts had surgery alone. Few palliative pts had chemotherapy, largely due to poor clinical status. Our data suggest that outcomes in both curative and palliative ECRF pts may be limited by the ability to tolerate standard of care treatments.

[Table: see text]

Isosbestic light absorption by metallic dimers: effect of interparticle electromagnetic coupling

Isosbestic plasmonic nanostructures, which feature an invariance of optical absorption and heat generation upon varying the incident light polarization, have broad application in many fields such as nanochemistry, optical nanoantennas, and microbubble formation. In this study, we focus on the isosbestic optical absorption by metallic dimers and systematically investigate the coupling between two interacting particles by using both the superposition T-matrix method and dipole approximation model. We observe that the interparticle coupling effects on particle absorption can be both positive and negative, compared to an isolated particle. Meanwhile, the optical absorption properties of spheres with small size parameters can realize more flexible control through changing the sphere size, interparticle distance, and incident light wavelength. For illuminations with incident light propagating perpendicularly to the line joining the centers of the two spheres, isosbestic conditions will be satisfied as long as the absorption efficiencies for transverse and longitudinal illuminations are equal. For transverse illuminations along the dimer axis, the ratio of absorption efficiency of the two metallic spheres presents the fluctuation change with the interparticle distance. Owing to the strong interparticle coupling effects, it even leads to the absorption efficiency of the far sphere being higher than that of the near sphere. Our results are aimed at expanding our understanding of the interparticle electromagnetic coupling effects on isosbestic light absorption in plasmonic nanoparticle systems.

Clinicopathological features and treatment outcomes of young patients with gastric and esophageal cancers

325

Background: Gastric and esophageal (GE) cancers most commonly occur in older adults in their 60’s. There are inconsistent reports about prognosis in adolescent and young adult (AYA) pts, and treatment patterns and outcomes in this population have not been well characterized. Methods: A retrospective analysis was performed for AYA (age < 40) pts with GE cancers who presented to Princess Margaret Cancer Centre from 2008 to 2016. The Kaplan-Meier method was used to analyze progression free (PFS) and overall survival (OS). Results: We identified 57 AYA GE cancer pts (30 gastric, 27 esophageal). Features at diagnosis included: median age 35, 51% female (70% in gastric, 30% in esophageal), 82% with performance status 0-1, 83% Charlson Comorbidity Index 0, 54% stage IV. For gastric pts, 53% had diffuse histology and 47% had signet ring adenocarcinoma. There was a negative family history of gastric or esophageal cancer in 77% of pts. Curative intent treatment was used in 23 pts, palliative in 34. In curative pts, 48% had neoadjuvant therapy, 52% had upfront surgery. Of pts who underwent surgery, 57% had T3 or T4a disease and 38% had N2 or N3 disease. Median OS in curative pts was 39.9 months (95% CI 19.7-69.9), with a 5-year OS rate of 37% (95% CI 20-67). Of the palliative pts, 91% had chemotherapy. First line chemotherapy was a triplet regimen in 80%, doublet in 13%. The median number of treatment cycles on first line chemotherapy was 6, with a median PFS of 7.4 months (95% CI 5.4-10.5). At progression, 14 pts had second line treatment, 3 pts had third line and only 1 pt was treated beyond third line. Median OS in palliative pts was 12.1 months (95% CI 8-21.3). Conclusions: Consistent with the literature, our gastric AYA pts had increased female predominance and diffuse histology. Many AYA pts had advanced disease at diagnosis, with over half of pts presenting with metastatic disease. In both the curative and palliative setting, AYA pts did not have better survival outcomes despite being young with few comorbidities, suggesting they may have more aggressive biology.

Light scattering by densely packed optically soft particle systems, with consideration of the particle agglomeration and dependent scattering

Light scattering and radiative transfer in optically soft particle systems are important problems in many fields of natural sciences and engineering, such as biology, ocean optics, atmospheric science, solar energy utilization, and so on. Due to the effects of particle agglomeration and dependent scattering, the radiative transfer problem will become more complex with the increase of particle volume fraction. In this study, the scattering properties and radiative transfer characteristics of densely packed optically soft particle systems, with consideration of the effects of dependent scattering and particle agglomeration, are investigated. The dependent scattering properties of densely packed silicon-dioxide spherical particles embedded in water are calculated by using the Lorenz-Mie theory and Percus-Yevick sticky hard-sphere model. The directional-hemispherical reflectance of the dispersed plane-parallel layer is obtained by using the Monte Carlo method. The results show that dependent scattering and particle agglomeration have significant influence on the scattering properties of particles. With the increase of particle agglomeration degree, the scattering coefficients and asymmetry factors of the particles increase obviously, which can be even larger than the results for independent scattering under certain circumstances. Due to the combined interaction of multiple scattering, dependent scattering, and particle agglomeration, for different size particles, the variation tendency of the hemispherical reflectance is obviously different with increasing particle agglomeration degree.

Effect of host medium absorption on polarized radiative transfer in dispersed media

This paper focuses on polarized radiative transfer in a thin layer composed of titanium dioxide particles while considering the effect of host medium absorption on particle scattering. The single-scattering properties of particles in an absorbing medium are calculated using the modified Lorenz-Mie program recently developed based on the first-principles theory of electromagnetic scattering, and the vector radiative transfer equation is solved by using the spectral element method. The relative errors of Stokes parameters caused by using the conventional Lorenz-Mie theory are systemically investigated. The results show that neglecting the effect of host medium absorption on particle scattering has a more significant impact on the radiation intensity than the polarization components in most cases. Meanwhile, the relative errors of Stokes parameters induced by using the conventional Lorenz-Mie theory obviously increase with the increase of the host medium absorption index and particle size parameter. Due to the larger scattering coefficients and scattering albedos (i.e., for the case of particle size parameter x=10.0 in this study), the relative errors of Stokes parameters of monodisperse particles are obviously larger than those of polydisperse particles. Moreover, it is found that the relative errors of the Stokes parameters change nonlinearly with the particle volume fraction, especially for large size particles.

3D nano-bridge-based SQUID susceptometers for scanning magnetic imaging of quantum materials

We designed and fabricated a new type of superconducting quantum interference device (SQUID) susceptometers for magnetic imaging of quantum materials. The 2-junction SQUID sensors employ 3D Nb nano-bridges fabricated using electron-beam lithography. The two counter-wound balanced pickup loops of the SQUID enable gradiometric measurement and they are surrounded by a one-turn field coil for susceptibility measurements. The smallest pickup loop of the SQUIDs were 1 μm in diameter and the flux noise was around 1 μФ₀/√Hz at 100 Hz. We demonstrate scanning magnetometry, susceptometry and current magnetometry on some test samples using these nano-SQUIDs.

Prognostic significance of sarcopenia in metastatic esophageal squamous cell carcinoma

4068

Background: Sarcopenia is defined as low skeletal muscle mass and represents a quantifiable marker of frailty. Disease related symptoms of anorexia, nausea and dysphagia, in addition to reduced physical activity contribute to muscle wasting in metastatic esophageal squamous cell cancer (MESCC) patients. This study set out to evaluate the prognostic utility of sarcopenia and its association with nutritional indices. Methods: MESCC patients (pts) with available abdominal CT imaging, attending Princess Margaret Cancer Centre between 2011 and 2016, were identified from the institutional database. Skeletal muscle index (SMI), normalized by height, was calculated at the third lumbar (L3) vertebra using SliceOMatic software. SMI cutoffs for sarcopenia were 34.4cm2/m2 in females and 45.4cm2/m2 in males based on previously established consensus. Nutritional risk index (NRI) was calculated using weight and albumin with malnutrition defined as < 97.5. Results: Of the 58 pts analyzed, 26 presented with de novo MESCC, median age was 64 (range 48-85), 30 pts were ECOG PS ≤1 and 45% received systemic therapy. 93% of pts experienced weight loss > 5% in the 3 months preceding diagnosis and median BMI was 20.4 (range 16.3-34.9). Twenty-four (41%) pts were sarcopenic (SP) with differences in BMI and NRI (p < 0.05) compared to non-sarcopenic (NSP) pts. Median BMI in SP pts was 18.9 (16.3-25.6), 46% had a BMI < 18.5 and none were obese (BMI ≥ 30). By NRI, 58% of SP pts were malnourished. Males comprised 71% of SP pts (p = 0.03) but no difference from NSP MESCC pts was identified with age, race, ECOG PS or smoking status with univariate analysis. Median overall survival (OS) was 6 months; 4.2 in SP pts and 6.2 in NSP pts. Significant difference was identified with NRI (p = .0.009) but not sarcopenia (p = 0.247) or BMI (p = 0.393). With a multi-variate Cox model for NRI and sarcopenia, including age, sex, race, and ECOG PS, only ECOG PS was a significant predictor of mortality, HR for 2-3 vs 0-1 of 5.4 (2.5-11.9) p < 0.001. Conclusions: Sarcopenia at diagnosis was not associated with OS. NRI was superior to BMI alone with respect to discriminating pt outcomes, however ECOG PS was the only measure significantly associated with survival.

Impact of adjuvant therapy in patients with a microscopically positive margin after resection for gastroesophageal cancer

4069

Background: A microscopically positive (R1) resection margin following resection for gastroesophageal (GE) cancer has been documented to be a poor prognostic factor. The optimal strategy and impact of different modalities of adjuvant treatment for an R1 resection margin remain unclear. Methods: A retrospective analysis was performed for patients (pts) with GE cancer treated at the Princess Margaret Cancer Centre from 2006-2016. Electronic medical records of all pts with an R1 resection margin were reviewed. Kaplan-Meier and Cox proportional hazards methods were used to analyze recurrence free survival (RFS) and overall survival (OS) with stage and neoadjuvant treatment as covariates in the multivariate analysis. Results: We identified 78 GE cancer pts with an R1 resection. 11% had neoadjuvant chemotherapy, 14% chemoradiation (CRT), 75% surgery alone. 28% had involvement of the proximal margin, 13% distal, 56% radial, 3% had multiple positive margins. By the American Joint Committee on Cancer 7th edition classification, 88% had a pT3-4 tumour, 66% pN2-3 nodal involvement, 64% grade 3, 68% with lymphovascular invasion. 3% were pathological stage I, 21% stage II and 74% stage III. Adjuvant therapy was given in 46% of R1 pts (24% CRT, 18% chemotherapy alone, 3% radiation alone, 1% reoperation). Median RFS for all pts was 12.6 months (95% CI 10.3-17.2). Site of first recurrence was 71% distant, 16% locoregional, 13% mixed. Median OS was 29.3 months (95% CI 22.9-50) for all pts. The 5 year survival rate was 23% (95% CI 12%-43%). There was no significant difference in RFS (log-rank test p = 0.63, adjusted p = 0.14) or OS (log-rank test p = 0.68, adjusted p = 0.65) regardless of adjuvant therapy. Conclusions: Most pts with positive margins after resection for GE cancer had advanced pathologic stage and prognosis was poor. Our study did not find improved RFS or OS with adjuvant treatment and only one pt had reresection. The main failure pattern was distant recurrence, suggesting that pts being considered for adjuvant RT should be carefully selected. Further studies are required to determine factors to select pts with good prognosis despite a positive margin, or those who may benefit from adjuvant treatment.

Surveillance and outcomes after curative resection for gastroesophageal adenocarcinoma (GEAC)

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Background: Although commonly performed, evidence supporting routine surveillance testing (SvT) in patients (pts) with resected GEAC is lacking. We evaluated patterns of relapse, frequency of salvage therapy and outcomes among pts with resected GEAC who underwent surveillance. Methods: Between 2011 and 2016, 210 consecutive pts with GEAC followed at Princess Margaret Cancer Center after resection were reviewed. SvT was any investigation performed in the absence of pt-reported symptoms, abnormal physical exam findings, or bloodwork. Relapse patterns were classified as locoregional (LRR; surgical anastomosis/gastroesophageal lumen/regional nodes) or distant (DR; beyond locoregional). Time-to-relapse (TTR) and overall survival (OS) were calculated from initial diagnosis, post recurrence survival (PRS) from initial relapse. Results: Median age was 64.1 years. Esophageal (14%), gastroesophageal junction (40%), and gastric adenocarcinomas (45%) were treated with surgery alone (29%), surgery plus perioperative chemotherapy (26%) or surgery plus chemoradiation (45%). SvT included imaging (71%), endoscopy (19%), tumor markers (6%), and clinical visits alone (9%). After median follow-up of 38.3 months (mo) (range 5.6-122.3), 3- and 5-year OS rates were 68% (95% confidence interval (CI) 62-75%) and 56% (95% CI 49-64%) respectively. Among 97 relapses (46%), 51 were detected by SvT, 45 by symptoms. Relapse patterns included LRR alone (4%), DR alone (86%) and both (10%). The majority of relapses (93%) occurred within 3 years. Pts with SvT-detected relapse had similar median TTR (16.2 vs 13.3 mo, p = 0.40) but longer PRS (16.5 vs 4.6 mo, p < 0.001) and OS (36.2 vs 23.7 mo, p = 0.004) than pts with symptomatic relapse. Salvage therapy in 4 pts (2%) resulted in post recurrence disease-free survival ≥2 years. Duration of palliative chemotherapy was similar between 28 pts with SvT-detected relapse and 18 pts with symptomatic relapses (3.9 vs 3.3 mo, p = 0.64). Conclusions: Following curative resection, 96% of relapses were distant. Routine SvT rarely enabled successful salvage therapy and did not extend duration of palliative chemotherapy. Longer OS in SvT-detected relapses was not due to earlier disease detection. These findings do not support routine SvT in pts with resected GEAC.

Prognostic significance of malnutrition in metastatic esophageal squamous cell carcinoma

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Background: Disease related symptoms including anorexia, nausea and dysphagia lead patients with esophageal cancer to become malnourished. Malnourishment can result in systemic inflammation, reduced treatment tolerance, poorer quality of life and decreased overall survival. Currently weight loss is the main clinical measure of malnutrition, and thus we set out to evaluate the prognostic utility of alternative screening tools of malnutrition. Methods: Patients with metastatic esophageal squamous cell cancer (MESCC) attending the Princess Margaret Cancer Centre, between January 2011 and December 2016, were identified from the institutional gastroesophageal database. Nutritional Risk Score (NRS), Nutritional Risk Index (NRI) and Neutrophil Lymphocyte Ratio (NLR) were calculated and correlated with clinical-pathological variables and survival. Malnutrition was defined as NRS ≥ 3, NRI < 97.5 and NLR ≥ 3. Results: Of the 64 consecutive patients, 30 (47%) presented with de novo metastatic disease and 34 (53%) with recurrence. The median age was 62 years (range 40-85), 47 patients were ECOG PS ≤ 2 and 29 (45%) received systemic chemotherapy. 90% of patients experienced weight loss > 5% prior to diagnosis and median BMI was 20.1 (range 14.3-34.9). NRI identified 37 (58%) and NRS 45 (70%) patients as malnourished. Both were associated with poorer ECOG PS (p = 0.012 and p = 0.027 respectively). No difference was identified with sex, smoking status or albumin with univariate analysis. NRI did not associate significantly with age. Median overall survival was 5months; 8.1-9 months with normal nutrition and 2.8-3.2 months in malnourished patients. Kaplan Meier analysis revealed significant difference in overall survival (malnutrition vs. normal nutrition) using NRS (p = 0.029) and NRI (p = 0.001) but not weight (p = 0.509) or NLR (p = 0.69). Conclusions: Patients with MESCC identified as malnourished at the time of diagnosis have inferior survival outcomes. Malnutrition tools are superior to weight alone with respect to discriminating outcomes in this patient population. Further investigation is needed in larger patient cohorts; to identify those at risk, initiate early supportive interventions and improve patient outcomes.

Impact of adjuvant therapy in patients with a microscopically positive margin after resection for gastroesophageal cancer

164

Background: A microscopically positive (R1) resection margin following resection for gastroesophageal (GE) cancer has been documented to be a poor prognostic factor. The optimal strategy and impact of different modalities of adjuvant treatment for an R1 resection margin remain unclear. Methods: A retrospective analysis was performed for patients (pts) with GE cancer treated at the Princess Margaret Cancer Centre from 2006-2016. Electronic medical records of all pts with an R1 resection margin were reviewed. Kaplan-Meier and Cox proportional hazards methods were used to analyze recurrence free survival (RFS) and overall survival (OS) with stage and neoadjuvant treatment as covariates in the multivariate analysis. Results: We identified 78 GE cancer pts with an R1 resection. 11% had neoadjuvant chemotherapy, 14% chemoradiation (CRT), 75% surgery alone. 28% had involvement of the proximal margin, 13% distal, 56% radial, 3% had multiple positive margins. By the American Joint Committee on Cancer 7th edition classification, 88% had a pT3-4 tumour, 66% pN2-3 nodal involvement, 64% grade 3, 68% with lymphovascular invasion. 3% were pathological stage I, 21% stage II and 74% stage III. Adjuvant therapy was given in 46% of R1 pts (24% CRT, 18% chemotherapy alone, 3% radiation alone, 1% reoperation). Median RFS for all pts was 12.6 months (95% CI 10.3-17.2). Site of first recurrence was 71% distant, 16% locoregional, 13% mixed. Median OS was 29.3 months (95% CI 22.9-50) for all pts. The 5 year survival rate was 23% (95% CI 12%-43%). There was no significant difference in RFS (log-rank test p= 0.63, adjusted p= 0.14) or OS (log-rank test p= 0.68, adjusted p= 0.65) regardless of adjuvant therapy. Conclusions: Most pts with positive margins after resection for GE cancer had advanced pathologic stage and prognosis was poor. Our study did not find improved RFS or OS with adjuvant treatment and only one pt had reresection. The main failure pattern was distant recurrence, suggesting that pts being considered for adjuvant RT should be carefully selected. Further studies are required to determine factors to select pts with good prognosis despite a positive margin, or those who may benefit from adjuvant treatment.

Surveillance and outcomes after curative resection for gastroesophageal adenocarcinoma (GEAC)

162

Background: Although commonly performed, the benefit of routine surveillance testing (SvT) following curative resection of GEAC is undefined. We aimed to determine frequency of successful salvage therapy (SST) in patients (pts) with relapsed GEAC who were surveyed post curative therapy. Methods: Between 2011 and 2016, 210 consecutive pts with locally advanced GEAC underwent curative surgery and subsequent surveillance at Princess Margaret Cancer Center. SST was defined as any potentially curative therapy for recurrence which resulted in post-recurrence survival (PRS) two years without further relapse. Time-to-event outcomes were analyzed using Kaplan-Meier and Cox regression methods. Results: Median age was 64.1 years. Esophageal (14%), gastroesophageal junction (41%), and gastric adenocarcinomas (45%) were included. Pts received surgery alone (29%), surgery with perioperative chemotherapy (26%) or perioperative chemoradiation (45%) as primary curative therapy. At median follow-up of 33.6 months (m, range 6.0-122.4), 3- and 5-year overall survival (OS) rates were 68% (95% CI 61-75%) and 59% (95% CI 51-68%) respectively. SvT modalities included imaging (69%), endoscopy (19%), tumor markers (4%), and clinical visits only (9%). Recurrences occurred in 95 (45%) pts, 51% were surveillance-detected (SvDR), and 47% were non-SvDR. Types of recurrences included locoregional only (4%), distant (87%) or both (9%). Salvage therapy was attempted in 14 pts (7%) with SvDR and 1 with non-SvDR. In four pts with SvDR (1.9%) salvage therapy was successful with chemoradiation or surgery perioperative chemotherapy, six were unsuccessful, and 5 had immature follow-up. Compared with pts with non-SvDR, pts with SvDR had longer median OS (34.8 vs. 24.0m, p=0.03) and PRS (14.4 vs. 4.8m, p < 0.001), and similar time-to-relapse (15.6 vs. 12.0m, p = 0.67). Palliative chemotherapy was administered in 25 pts with SvDR and 18 pts with non-SvDR with similar median duration (3.5m vs. 3.3m, p=0.64). Conclusions: Following curative therapy, 96% of relapses were distant. SvT enabled SST in only 1.9% of pts, and did not extend duration of palliative chemotherapy. These data do not support the use of routine SvT in resected GEAC.

[Minocycline inhibits formalin-induced inflammatory pain and the underlying mechanism]

OBJECTIVE

To unravel the underlying mechanism of minocycline in formalin-induced inflammatory pain, and to investigate the effects of minocycline on synaptic transmission in substantia gela-tinosa (SG) neurons of rat spinal dorsal horn.

METHODS

Behavioral and immunohistochemistry experiments: 30 male Sprague-Dawley (SD) rats (3-5 weeks old) were randomly assigned to control (n=8 rats), model (n=8 rats), saline treatment model (n=6 rats) and minocycline treatment model (n=8 rats) groups. The control group was subcutaneously injected with normal saline on the right hindpaws. Acute inflammatory pain model was established by injecting 5% (volume fraction) formalin into the right hindpaws. The rats in the latter two groups received intraperitoneal injection of saline and minocycline 1 h before the formalin injection, respectively. The time of licking and lifting was recorded every 5 min within 1 h after the subcutaneous injection of normal saline or formalin for all the groups, which was continuously recorded for 1 h. One hour after the pain behavioral recording, the spinal cord tissue was removed following transcardial perfusion of 4% paraformaldehyde. The expression of c-Fos protein in spinal dorsal horn was observed by immunohistochemistry. Electrophysiological experiment: In vitro whole-cell patch-clamp recordings were performed in spinal cord parasagittal slices obtained from 26 male SD rats (3-5 weeks old). Two to five neurons were randomly selected from each rat for patch-clamp recording. the effects of minocycline, fluorocitrate and doxycycline on spontaneous excitatory postsynaptic currents (sEPSCs) or spontaneous inhibitory postsynaptic currents (sIPSCs) of SG neurons were investigated.

RESULTS

Compared with the control group, both the licking and lifting time and the expression of c-Fos protein in ipsilateral spinal dorsal horn of the model group were significantly increased. Intraperitoneal injection of minocycline largely attenuated the second phase of formalin-induced pain responses (t=2.957, P<0.05). Moreover, c-Fos protein expression was also dramatically reduced in both the superficial lamina (I-II) and deep lamina (III-IV) of spinal dorsal horn (t_I-II=3.912, t_III-IV=2.630, P<0.05). On the other side, bath application of minocycline significantly increased the sIPSCs frequency to 220%±10% (P<0.05) of the control but did not affect the frequency (100%±1%, t=0.112, P=0.951) and amplitude (98%±1%, t=0.273, P=0.167) of sEPSCs and the amplitude (105%±3%, t=0.568, P=0.058) of sIPSCs. However, fluorocitrate and doxycycline had no effect on the frequency [(99%±1%, t=0.366, P=0.099); (102%±1%, t=0.184, P=0.146), respectively] and amplitude [(98%±1%, t=0.208, P=0.253); (99%±1%, t=0.129, P=0.552), respectively] of sIPSCs.

CONCLUSION

Minocycline can inhibit formalin-induced inflammatory pain and the expression of c-Fos protein in spinal dorsal horn. These effects are probably due to its enhancement in inhibitory synaptic transmission of SG neurons but not its effect on microglial activation or antibiotic action.

Safety evaluation of zinc methionine in laying hens: Effects on laying performance, clinical blood parameters, organ development, and histopathology

The study was conducted to investigate whether high-dose zinc methionine (Zn-Met) affected the safety of laying hens, including laying performance, hematological parameters, serum chemical parameters, organ index, and histopathology. A total of 540 20-week-old Hy-Line White laying hens was randomly allocated to 6 groups with 6 replicates of 15 birds each. Birds were fed diets supplemented with 0 (control), 70, 140, 350, 700, or 1,400 mg Zn/kg diet as Zn-Met. The experiment lasted for 8 wk after a 2-week acclimation period. Results showed that dietary supplementation with 70 or 140 mg Zn/kg diet as Zn-Met significantly increased average daily egg mass (ADEM), laying rate (LR), and feed conversion ratio (FCR) (P < 0.05) and lowered broken and soft-shelled egg ratio (BSER) (P < 0.05) in comparison with the control group; no significant differences were detected among hens fed with 0, 350, or 700 mg Zn/kg as Zn-Met (P > 0.05); hens administered 1,400 mg Zn/kg showed a significant increase in BSER and remarkable decreases in ADEM, LR, and FCR (P < 0.001). There were no significant differences among hens receiving 0, 70, 140, 350, or 700 mg Zn/kg as Zn-Met in serum chemical parameters (P > 0.05); supplementation with 1,400 mg Zn/kg as Zn-Met remarkably elevated the concentrations of serum total bilirubin (TBILI), glucose (GLU), uric acid (UA), and creatinine (CRE) (P < 0.001), and enhanced activities of serum glutamic oxalacetic transaminase (GOP) and alkaline phosphatase (AKP) (P < 0.001) compared with the control group. No significant histopathological changes were found in hens administered 0, 70, 140, 350, or 700 mg Zn/kg as Zn-Met, while significant histological lesions were observed in the heart, liver, lung, and kidney tissues of hens receiving 1,400 mg Zn/kg as Zn-Met. No significant differences were detected in hematological parameters or organ index (P > 0.05). In conclusion, a nominal Zn concentration of 700 mg/kg as Zn-Met is considered to be no-observed-adverse-effect level following daily administration to hens for 56 days.

Management of metastatic gastric and esophageal cancer in older adults

163

Background: Older adults are under-represented or excluded from pivotal trials of palliative chemotherapy for metastatic gastric and esophageal (GE) cancers. Little is known about how older patients are treated in the real world. The objective of this study was to examine the impact of age on treatment and survival. Methods: Patients aged ≥65 years were identified from a retrospective database of patients with metastatic GE cancer (Princess Margaret Cancer Centre; 2011-2016). The impact of age ≥75 years (old-old) versus (vs.) 65-74 years (young-old) on treatment and survival was assessed using multivariable logistic and Cox proportional hazard regression models, respectively, adjusted for known prognostic factors including sex, comorbidity, primary site, histology, grade, stage at initial diagnosis, metastatic sites, and chemotherapy use. Results: Of 183 patients, median age was 72 (range 65-92) years; 31% were old-old. Old-old patients were less likely to be treated with any chemotherapy (12.3% vs. 45.2% young-old; adjusted odds ratio = 0.12 (95% confidence interval (CI) 0.05-0.31)). With a median follow-up of 5.7 months, 135 (74%) had died during follow-up; median overall survival (OS) was 5.2 months (mo) for the old-old vs. 8.4 mo (young-old). There was no significant difference in survival between the two groups after adjustment for known prognostic factors (old-old vs. young-old: univariable hazard ratio (HR) 1.75 (95% CI 1.2-2.5); adjusted HR 1.1 (95% CI 0.7-1.7). Treatment with any chemotherapy was associated with an improvement in survival: adjusted HR 0.34 (95%CI 0.22-0.52). Conclusions: In this single-centre study of older adults with metastatic GE cancer, there was an overall low rate of treatment with chemotherapy; those ≥75 were rarely treated. After accounting for known prognostic factors, there was no observed difference in survival between patients ≥75 and those 65 to 74. Comprehensive geriatric assessment may improve treatment selection in the older population. [Table: see text]

Outcomes for advanced HER2-positive gastroesophageal cancer by anatomical location: Experience from the Princess Margaret Cancer Centre

131

Background: The landmark ToGA trial established trastuzumab (T) based therapy as the standard of care for advanced HER2+ gastric and gastroesophageal junction cancer. However, outcomes for T based therapy for HER2+ esophageal cancer have not been well characterized. Methods: We conducted a retrospective analysis of patients (pts) with HER2+ gastroesophageal cancer receiving T based therapy at our institution from 2011-2016. Distal esophagus ( < 35 cm) and Siewert type I/II tumours were defined as esophageal (E). Siewert type III and stomach tumours were defined as gastric (G). Trained abstractors collected pt demographics and treatment details. Overall survival (OS) and progression-free survival (PFS) were calculated from the date of first T treatment. Chi-square tests, t-tests and Cox proportional hazards models were applied where appropriate. Results: We identified 87 pts with advanced HER2+ disease. 62% (n = 54) had de novo metastatic (M1) disease. 57 patients were treated with T based therapy, with median age 57 years (IQR 48-67), 91% baseline performance status 0-1, 19% female, and 7% Asian. 63% (n = 36) had E and 37% (n = 21) had G primary tumours. 67% (n = 38) presented with M1 disease. 33% (n = 19) underwent surgery with curative intent and received T based therapy at recurrence. Baseline characteristics were balanced between the E and G groups. Survival data were available for 51 patients. The E and G groups did not have significant differences in PFS (median 9.5 vs. 9.1 months, HR 0.89 (95% CI 0.44-1.80), p = 0.74) or in OS (median 15.8 vs. 14.2 months, HR 0.88 (95% CI 0.42-1.82), p = 0.73). 63% (n = 36) were treated with subsequent systemic therapy after progression on T, with 23 receiving one line, 9 receiving two lines and 4 receiving three additional lines of treatment. The number subsequent therapies received was similar between E and G groups. Conclusions: Although patients with distal esophagus tumours were not included in the ToGA trial, our analysis suggests that patients with E and G tumours had similar outcomes. Our contemporary cohort had comparable survival outcomes relative to patients receiving T in the ToGA trial (median PFS = 6.7 months, median OS = 13.8 months).

Relationship between human epidermal growth factor receptor 2 (HER2) status and central nervous system metastases in gastroesophageal cancer

145

Background: Central nervous system (CNS) metastases (mets) in gastroesophageal (GE) cancers are rare. There have only been limited studies examining the role of HER2 status in CNS mets in GE cancers. Methods: A retrospective analysis was performed for patients (pts) treated for GE cancers at the Princess Margaret Cancer Centre from 2011-2016. Quantitative and qualitative data were collected for all pts with CNS mets. Kaplan-Meier method was used to calculate overall survival (OS) and CNS progression free survival (PFS) for CNS mets pts. Results: Of 34 GE cancer pts diagnosed with CNS mets, 11 were HER2+, 11 HER2- and 12 had unknown HER2 status. Median time from initial cancer diagnosis to CNS mets was 10.3 months (13.4 in HER2+, 5.8 in HER2-, 11.7 in HER2 unknown). Characteristics at CNS mets diagnosis included: median age 63; 85% male; 74% had extracranial systemic mets; performance status ECOG 0-1 (64%), 2 (12%), 3-4 (24%). Treatment for CNS mets is shown in Table 1. Median OS from diagnosis of CNS mets was 6.1 months (95%CI 3.2-16.4) for all pts, 17.1 (95%CI 9.9-NA) in HER2+, 1.8 (95%CI 0.6-NA) in HER2-, 6.0 (95%CI 1.9-NA) in HER2 unknown, p=0.01. Median OS from initial cancer diagnosis was 18.5 months (95%CI 13.6-33.7) for all pts, 28.9 (95%CI 21.32-NA) in HER2+, 10.8 (95%CI 6.37-NA) in HER2-, 18.6 (95%CI 10-NA) in HER2 unknown, p=0.015. The 1 year CNS PFS rate was 35% (95%CI 22.1 – 55.5%) for all pts, 53% (95%CI 29.9 – 94%) in HER2+, 18.2% (95%CI 5.3 – 63.7%) in HER2-, 33% (95%CI 15 – 74.2%) in HER2 unknown, p=0.053. Conclusions: HER2+ pts tended to develop CNS mets later than HER2-. HER2+ pts were more likely to receive CNS-directed interventions, with more HER2+ pts having surgery for CNS mets while more HER2- had supportive care. This analysis is the first to suggest that in pts with CNS mets, HER2+ pts had longer survival than HER2-, both from initial diagnosis and after developing CNS metastases.[Table: see text]

Comparison of bimodality versus trimodality therapy for esophageal or gastroesophageal junction (GEJ) cancer: Experience from the Princess Margaret Cancer Centre

122

Background: There are no phase 3 trials comparing definitive chemoradiation (bimodality) versus. perioperative chemoradiation (trimodality) for locoregional esophageal/GEJ cancer. Methods: A retrospective analysis (2011-2015) compared bimodality and trimodality therapy in patients (pts) with locoregional esophageal/GEJ cancer treated with curative intent. Overall survival (OS) and disease-free survival (DFS) were calculated from the date of diagnosis. Uni- and multivariable Cox proportional hazards regression adjusted for patient and disease factors. Results: Of 108 patients, 82 (76%) were male. Mean ages were 69.5 ± 11.0 years (bimodality; N = 41) and 60.5 ± 11.1 years (trimodality; N = 67). For bimodality pts, 37% had adenocarcinoma and 63% had squamous cell carcinoma (SCC). For trimodality pts, 79% had adenocarcinoma and 21% had SCC (p < 0.0001). Bimodality pts received a higher radiation dose compared to trimodality pts (50.1 ± 6.7 vs. 45.2 ± 6.4 Gy). Median follow-up was 49.3 months. We found no significant OS difference between bimodality (27.0 months) and trimodality therapy (29.8 months) in the overall cohort (p = 0.57) (4 year OS rate: 42% vs. 38%). In the subgroup with adenocarcinoma histology, trimodality therapy significantly improved OS and DFS compared to bimodality (OS: 31.8 vs. 10.4 months, hazard ratio (HR) 0.34, 95% confidence interval (CI) 0.18-0.66, p = 0.001; DFS: 15.0 vs. 6.7 months; HR 0.39, 95%CI 0.21-0.73, p = 0.003). In the SCC subgroup, median OS and DFS were similar (OS: not reached vs. 29.2 months, p = 0.48; DFS: 27.0 vs. 24.0, p = 0.96). Using multivariable regression with AIC backward selection, the only retained prognostic factors were treatment modality (p = 0.06) and histology (p = 0.01). Conclusions: Our findings support preferential use of trimodality therapy for pts with adenocarcinoma histology given superior OS and DFS, whereas bimodality and trimodality therapy appeared comparable in pts with SCC histology. Pending confirmation in a larger series with longer follow-up, these findings suggest differential treatment algorithms for locoregional esophageal and GEJ cancer based on tumor histology.

Patterns of recurrence and outcomes after curative resection of locally advanced HER2-positive gastroesophageal cancer (HPGEC)

147

Background: Literature on recurrence and outcomes of HPGEC is scarce. The aim of this study was to determine pattern of recurrence and outcomes after curative intent surgery for locally advanced HPGEC. Methods: A retrospective database was used to identify consecutive patients with gastroesophageal adenocarcinomas undergoing curative intent resection between 2011 and 2016 at the Princess Margaret Cancer Centre. Clinico-demographic data were extracted from the electronic health record. Patterns of relapse are classified as nonvisceral (defined as recurrences in the bone, peritoneal or both), visceral (not nonvisceral, including the brain), or both. Time to relapse (TTR) and overall survival (OS) were calculated from date of histologic diagnosis. Results: Of 45 patients with HPGEC, 78% were male, and 91% were non-Asian. Median age was 64.4 years (interquartile range [IQR] 53, 70); 60% were gastroesophageal junction, 24% were gastric, and 16% were esophageal adenocarcinomas; 31% were poorly differentiated tumors while 68% had clinical or pathological node positive disease. Complete R0 resection occurred in 93%, and 84% had received perioperative therapy (31% with perioperative chemotherapy; 40% with pre-operative chemoradiation; 9% with post-operative chemoradiation). With a median follow-up time of 26.0 months. relapse rate of HPGEC at last follow-up was 78%. Among first relapses, 94% were distant, while 6% were local recurrences. Among distant relapses, visceral recurrences occurred in 85%, nonvisceral in 3%, and 12% patients had both visceral and nonvisceral recurrences. None had peritoneal only recurrence. Median TTR was 12.2 months (IQR 8.8, 23.5), while median post-recurrence survival was 9.7 months (IQR 4.7, 16.3). Of the entire cohort, 2-year OS was 53% and 3-year OS was 26%. Conclusions: More than three-quarters of patients with HPGEC experienced recurrence after curative intent multimodality therapy. Our results suggest that HPGEC rarely relapse with peritoneal only disease or local recurrence, thereby calling into question the utility for aggressive surveillance, pending verification from larger cohorts.

[Spinal analgesic mechanism of minocycline in formalin-induced inflammatory pain]

Objective: To investigate the spinal analgesic mechanism of minocycline in formalin-induced inflammatory pain. Methods: Behavioral test: Male Sprague-Dawley rats(3-5-week old) were randomly assigned into four groups: control, model, vehicle-controlled and minocycline group. Ten percent neutral formalin was injected subcutaneously into the right hind paw dorsum of the rats in model, vehicle-controlled and minocycline group. Normal saline was injected subcutaneously into the right hind paw dorsum of the rats in control group. Before 1 h of formalin injection, the rats in vehicle-controlled and minocycline group received intraperitoneal injection of saline and minocycline, respectively. Licking and lifting time was observed as the behavior results of inflammatory pain. Electrophysiologic experiment: In vitro spinal cord parasagittal slices were prepared from the same rats as above. The effect of minocycline on spontaneous inhibitory postsynaptic currents(sIPSCs) of substantia gelatinosa(SG) neurons was observed using whole-cell patch-clamp technique. Results: Compared with the control group, the licking and lifting time in the model group was significantly increased. Compared with the vehicle-controlled group, the licking and lifting time in the minocycline group was significantly decreased. Minocycline significantly increased the frequency(t=9.32, P<0.05)but not the amplitude(t=1.54, P>0.05) of sIPSCs of SG neurons, the frequency of sIPSCs of control and minocycline group were (2.5±0.3)Hz and (5.2±0.6)Hz, respectively. When calcium was removed from the extracellular solution, the frequency before and after minocycline perfusion were (0.9±0.1)Hz and (0.9±0.1)Hz, respectively, the amplitude before and after minocycline perfusion were (18.2±0.7)pA and (18.5± 0.6)pA, respectively, the difference of frequency or amplitude was not statistically significant(t=0.32, 0.82, all P>0.05). However, minocycline still increased the frequency of sIPSCs when glutamate receptor antagonists 6-Cyano-7-nitroquinoxaline-2, 3-dione(CNQX) and D-(-)-2-Amino-5-phosphonopentanoic acid(APV) were included in extracellular solution(t=13.51, P<0.05), the frequency of sIPSCs were (2.0±0.1)Hz and (4.3±0.4)Hz, respectively. Minocycline still increased the frequency of IPSCs when voltage-gated sodium channel blocker tetrodotoxin(TTX) were included in extracellular solution(t=8.67, P<0.05), the frequency of IPSCs were (2.2±0.2)Hz and (5.2±0.5)Hz. Conclusion: Minocycline can attenuate formalin-induced inflammatory pain which may be associated with its increase in the inhibitory synaptic transmission of SG neurons.

Outcomes for patients ≥75 years with localized gastroesophageal cancer: Experience from the Princess Margaret Cancer Centre

10037

Background: The optimal treatment and outcome for elderly patients (pts) with localized gastroesophageal (GE) cancer remains unclear as they are underrepresented in clinical trials. We aimed to assess survival in pts ≥75 years according to treatment received. Methods: A retrospective analysis was performed for all pts aged ≥75 years with GE cancer treated in 2012-2014. Frailty was measured using the Charlson comorbidity index (CCI) and ECOG performance status (PS). Overall survival (OS) and disease-free survival (DFS) were assessed via uni- and multivariable Cox proportional hazards regression, adjusting for demographics. Logistic regression analyses were used to examine factors impacting treatment choices. Results: Of 105 pts, median age was 81 years (range: 75-99), primary sites were esophageal (55%, with 43% squamous histology) and gastric (45%). Baseline characteristics included: PS: 0 (31%), 1 (42%), 2 (16%), 3 (10%), 4 (1%); and CCI: 0 (34%), 1 (25%), 2 (19%), ≥3 (22%). Treatment received included radiotherapy alone (RT) (31%); surgery alone (29%); surgery plus adjuvant chemotherapy (chemo) and/or RT (14%); chemoradiation alone (7%) and supportive care (18%). In univariable analyses; age < 85 (p = 0.003), PS < 2 (p = 0.03) and surgery (p < 0.001) were associated with improved OS. Chemo and RT, either alone or in combination, did not significantly improve OS. In multivariable analyses; surgery (HR 0.38, 95% CI 0.21-0.70, p = 0.002) was the only independent predictor for improved OS. Patients with good PS (p = 0.01), gastric disease site (p = 0.01) and adenocarcinoma histology (p = 0.02) were more likely to undergo surgery. Conclusions: At our institution, relatively few pts ≥75 years received multimodality therapy for localized GE cancers. Those pts ≥75 years who underwent surgery had excellent outcomes, but they were well-selected. Comprehensive assessment should be considered for pts ≥75 years with localized GE cancer to ensure optimal treatment selection, particularly given the potential benefit of surgery.

[Comparison of clinical outcomes of patients with non-small cell lung cancer harboring different types of epidermal growth factor receptor sensitive mutations after first-line EGFR-TKI treatment]

OBJECTIVE

To analyze whether there are differences in the efficacy and clinical outcomes to first-line tyrosine kinase inhibitors (TKI) therapy in Chinese patients with metastatic non-small-cell lung cancer (NSCLC) harboring different subtypes of epidermal growth factor receptor (EGFR) mutations.

METHODS

A retrospective analysis was made on the clinical data of stage ⅢB or Ⅳ NSCLC patients who were diagnosed by histology and received EGFR mutation test, in order to confirm if there is any difference between the therapeutic effects of TKIs as first-line therapy and the prognosis.

RESULTS

A total of 165 patients harboring EGFR exon 19 deletion (19del, n=71), exon 21 L858R mutation (L858R, n=80) or uncommon sensitive mutation (n=14) were treated with EGFR-TKIs for first-line treatment. The comparison among different groups of common types of sensitive mutations revealed that the objective response rate (ORR) of group 19del and group L858R were 57.8% and 45.0%, respectively (P=0.113). The disease control rate (DCR) was 93.0% and 93.8%, respectively (P=0.158). However, the ORR and DCR of uncommon sensitive mutation were 35.7% and 78.6%, which were significantly lower than that of the group 19del (P=0.035) and group L858R (P=0.020). The median progression-free survival (PFS) of group 19del, group L858R and uncommon sensitive mutation were 14.0 months, 7.8 months and 5.1 months, respectively (P=0.001). The median PFS of the group 19del was significantly longer than that of the group L858R (P=0.009). The median overall survival (OS) of these three groups had significant difference (22.8, 15.2 and 10.0 months) (P=0.048). But those of group 19del and group L858R were similar (P=0.152). The multivariate analysis indicated that ECOG-PS (P=0.030), cigarette smoking (P=0.013) and EGFR mutation types (P=0.034) are independent prognostic factors of OS.

CONCLUSIONS

For Chinese NSCLC patients with different types of sensitive mutation, there are differences between their efficacy and prognosis of EGFR-TKIs as first-line treatment. The PFS of group 19del is obviously longer than that of other types of sensitive mutations, but have no significant differences in OS. The PFS and OS of patients with common types of sensitive mutation are better than those with uncommon sensitive mutation.

[Efficiency and adverse effects of the effective therapy applying etoposide + cisplatin and its subsequent maintenance therapy with different durations in patients with small cell lung cancer]

OBJECTIVE

To explore the efficiency and adverse effects of the effective EP (etoposide + cisplatin) therapy and its subsequent maintenance therapy with different durations in patients with small cell lung cancer (SCLC).

METHODS

Clinical data of 104 SCLC patients diagnosed and treated at the Jilin Province Cancer Hospital between September 2010 and December 2013 were retrospectively analyzed.Among them, 35 patients were subsequently treated with a 4-week maintenance therapy following the original therapeutic regimen after the effective EP therapy (4-week maintenance therapy group), 35 patients were treated with a subsequent 6-week maintenance therapy (6-week maintenance therapy group), and 34 patients were treated without maintenance therapy (control group).52 patients were in limited stage, and 52 patients were in extensive stage. The progression-free survival (PFS), overall survival (OS) and adverse effects in the 4-week maintenance therapy group, 6-week maintenance therapy group and control group were analyzed.

RESULTS

The median PFS in the control group, 4-week maintenance therapy group and 6-week maintenance therapy group was 4.0, 3.5, and 4.0 months, respectively, and the median OS was 9.0, 10.0 and 12.0 months, respectively, showing no significant difference among the groups (P>0.05 for all). The median PFS was prolonged by 2 months as compared with the control group after the 4-week maintenance therapy in the patients with complete remission in first-line chemotherapy (P=0.041), while the median OS was not improved (P=0.131). Neither the median PFS nor median OS showed statistically significant difference between each two groups in the patients with partial remission in first-line chemotherapy (P>0.05 for all). In the limited stage, the median PFS in the control group, 4-week maintenance therapy group, and 6-week maintenance therapy group was 5.0, 6.5, and 4.0 months, respectively, and median OS was 11.0, 13.5, and 13.0 months, respectively, the differences showed no statistical significance (P>0.05 for all). In the extensive stage, the median PFS in the control group, 4-week maintenance therapy group, and 6-week maintenance therapy group was 3.0, 3.0, and 3.5 months, respectively, showing significant differences (P=0.015); the median OS was 6.5, 8.0, and 8.0 months, respectively, presenting no statistically significant differences (P=0.096). In addition, the PFS in the 6-week maintenance therapy group was significantly improved as compared with that in the control group (P=0.016). Compared with the control group, the incidence rates of nausea (grade 3-4), vomiting, hypodynamia, leukopenia, neutropenia, and thrombocytopenia in the 4-week maintenance therapy group and 6-week maintenance therapy group were increased significantly (P<0.05 for all), however, the side effects were tolerable.

CONCLUSION

Prolonging the treatment cycle of EP therapy can improve the PFS in SCLC patients in first-line CR chemotherapy and extensive stage.

Investigation of the spectral reflectance and bidirectional reflectance distribution function of sea foam layer by the Monte Carlo method

Spectral properties of sea foam greatly affect ocean color remote sensing and aerosol optical thickness retrieval from satellite observation. This paper presents a combined Mie theory and Monte Carlo method to investigate visible and near-infrared spectral reflectance and bidirectional reflectance distribution function (BRDF) of sea foam layers. A three-layer model of the sea foam is developed in which each layer is composed of large air bubbles coated with pure water. A pseudo-continuous model and Mie theory for coated spheres is used to determine the effective radiative properties of sea foam. The one-dimensional Cox-Munk surface roughness model is used to calculate the slope density functions of the wind-blown ocean surface. A Monte Carlo method is used to solve the radiative transfer equation. Effects of foam layer thickness, bubble size, wind speed, solar zenith angle, and wavelength on the spectral reflectance and BRDF are investigated. Comparisons between previous theoretical results and experimental data demonstrate the feasibility of our proposed method. Sea foam can significantly increase the spectral reflectance and BRDF of the sea surface. The absorption coefficient of seawater near the surface is not the only parameter that influences the spectral reflectance. Meanwhile, the effects of bubble size, foam layer thickness, and solar zenith angle also cannot be obviously neglected.

Identification and genetic mapping of the putative Thinopyrum intermedium-derived dominant powdery mildew resistance gene PmL962 on wheat chromosome arm 2BS

Powdery resistance putatively derived from Thinopyrum intermedium in the wheat line L962 is controlled by a single dominant gene designated PmL962 and mapped to chromosome arm 2BS. Powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is a destructive disease affecting the production of wheat (Triticum aestivum). Powdery mildew resistance was putatively transferred from Thinopyrum intermedium to the common wheat line L962, which conferred resistance to multiple Chinese Bgt isolates. Genetic analysis of the powdery mildew response was conducted by crossing the resistant line L962 with the susceptible line L983. Disease assessments of the F1, F2, and F2:3 populations from the cross L983/L962 indicated that resistance was controlled by a single dominant gene. A total of 373 F2:3 lines and 781 pairs of genomic simple sequence repeat (SSR) primers were employed to determine the chromosomal location of the resistance gene. The gene was linked to four publicly available and recently developed wheat genomic SSR markers and seven EST-STS markers. The resistance gene was mapped to chromosome arm 2BS based on the locations of the linked markers. Pedigree, molecular marker and resistance response data indicated that the powdery mildew resistance gene in L962 is novel. It was temporarily designated PmL962. It is flanked by Xwmc314 and BE443737at genetic distances of 2.09 and 3.74 cM, respectively, and located in a 20.77 cM interval that is co-linear with a 269.4 kb genomic region on chromosome 5 in Brachypodium distachyon and a 223.5 kb genomic region on rice (Oryza sativa) chromosome 4. The markers that are closely linked to this gene have potential applications in marker-assisted breeding.

Molecular cloning and single nucleotide polymorphism analysis of IGF2a genes in the common carp (Cyprinus carpio)

We studied whether two IGF2 transcripts in common carp are similar to those found in zebrafish. The full-length IGF2a cDNA contains a 5'-terminal untranslated region (UTR) of 105 bp, a 3'-terminal UTR of 1358 bp and an open reading frame of 612 bp, which encodes a 206-amino acid protein. A 6614-bp full-length IGF2a DNA molecule, including the 5'-flanking region, was isolated. Genomic DNA structure analysis revealed that the IGF2a gene contains four exons and three introns. Bioinformatics analysis indicated that the proteins encoded by IGF2a genes in common carp have one signal peptide and one apparent transmembrane region. Bootstrapping was performed 1000 times to obtain support values for each branch. The common carp IGF2a were clustered in one group, while the outgroup (common carp IGF1) clustered in another group. We identified two new single nucleotide polymorphisms in intron 2 of the gene. One polymorphism, A/N, can be found only in the Huanghe carp. The other polymorphism, C/N, can be found in both male Huanghe carp × female Heilongjiang carp and male Huanghe carp × female Jian carp. The second polymorphism, C/N, is primarily transferred from the male and may be related to heterosis.

A new cell culture system for infection with hepatitis B virus that fuses HepG2 cells with primary human hepatocytes

Hepatitis B virus (HBV) infection exhibits a very narrow host range and shows a strong tropism for liver parenchymal cells, however none of the previously established experimental models can reproduce the natural process of HBV infection. In the present study, primary human hepatocytes were fused with HepG2 cells to establish the hybrid HepCHLine-4 cell line with high susceptibility to HBV. The HepCHLine-4 cells expressed HBV-specific antigen when co-incubated with HBV-positive serum from a hepatitis B patient. Post-infection, HBV relaxed circular DNA and covalently closed circular DNA were detected in HepCHLine-4 cells using a nested polymerase chain reaction, and HBV-specific particles were visualized by electron microscopy of the culture media of HepCHLine-4 cells. HepG2 cells were not susceptible to HBV infection under the same conditions. The HepCHLine-4 cells can be sub-cultured for > 12 months while maintaining susceptibility to HBV and may, therefore, be useful for studying HBV infection and the viral life cycle in human hepatocytes.

A mutant α-amylase with only part of the catalytic domain and its structural implication

A truncated mutant alpha-amylase, Xa-S2, was obtained from Xanthomonas campestris wild type alpha-amylases (Xa-WT) through random mutagenesis that contained 167 amino acid residues (approx 65% shorter than that of Xa-WT). Secondary structure prediction implied that Xa-S2, would be unable to form the whole (beta/alpha)(8)-barrel catalytic domain and did not have the three conserved catalytic residues of wild type alpha-amylase, but it still displays the starch-hydrolyzing activity. Xa-S2 was prepared, characterized and compared to the recombinant wild-type enzymes. The K (m) for starch was 32 mg/ml; activity was optimal at pH 6.2 and 30 degrees C. In contrast, the K (m) for starch of Xa-WT was 8 mg/ml and optimal enzyme activity was at pH 6.0-6.2 and 45-50 degrees C. Our results suggested that Xa-S2 is a new amylase with a minimal catalytic domain for hydrolyzing substrates with of alpha-1,4-glucosidic bonds.

[Determination of impurities in a technical chlorpyrifos by gas chromatography with atomic emission detection]

Mass fraction of impurities in a technical chlorpyrifos sample may be obtained by selective determination on carbon (496 nm and 193 nm), chlorine(479 nm), and sulfur (181 nm) channels using gas chromatography with atomic emission detection(GC/AED). According to the formulas from GC/MS and analytical results from GC/AED, mass fraction of compounds may be calculated by internal standard of elements. The results for the same compound obtained from different elemental channels were consistent. This shows the responses of carbon, chlorine and sulfur on AED are independent on molecular structures. Moreover, the reliability of the qualitative results of impurities from GC/MS was proved. If the formulas from GC/MS were wrong, the results from different elemental channels on GC/AED would be different. The relative deviations were in the range of -3.4% to 5.8%. When standards are not available, the results from GC/AED are more reliable than those from GC/FID which usually depend on the area normalization without corrections. Pesticides and other complex organic mixtures may be analyzed reliably and expediently by this method.

[The effect of ginseng stem, leaf and rhizoma saponins on the formation of lipid peroxides in rats of various ages]

The effect of saponins isolated from the stem, leaf and rhizoma of panax ginseng on the formation of lipid peroxides in aged (30, 24 and 20 months) and middle-aged (14 months) wistar rats was studied with both in vivo and in vitro methods. The results showed: The formation of lipid peroxides increased with age in rats and mice: the two saponins of ginseng stem, leaf and rhizoma can obviously inhibit the lipid peroxidation in the serum (plasma) and liver homogenate of aged and middle-aged rats (p less than 0.05 and less than 0.001). The same effect was also shown in the aged LACA mouse (18 months) experiment.