Pathological regression of primary tumour and metastatic lymph nodes following chemotherapy in resectable OG cancer: pooled analysis of two trials

BACKGROUND

No definitive largescale data exist evaluating the role of pathologically defined regression changes within the primary tumour and lymph nodes (LN) of resected oesophagogastric (OG) adenocarcinoma following neoadjuvant chemotherapy and the impact on survival.

METHODS

Data and samples from two large prospective randomised trials (UK MRC OE05 and ST03) were pooled. Stained slides were available for central pathology review from 1619 patients. Mandard tumour regression grade (TRG) and regression of tumour within LNs (LNR: scored as present/absent) were assessed and correlated with overall survival (OS) using a Cox regression model. An exploratory analysis to define subgroups with distinct prognoses was conducted using a classification and regression tree (CART) analysis.

RESULTS

Neither trial demonstrated a relationship between TRG score and the presence or absence of LNR. In univariable analysis, lower TRG, lower ypN stage, lower ypT stage, presence of LNR, presence of well/moderate tumour differentiation, and absence of tumour at resection margin were all associated with better OS. However, the multivariable analysis demonstrated that only ypN, ypT, grade of differentiation and resection margin (R0) were independent indicators of prognosis. Exploratory CART analysis identified six subgroups with 3-year OS ranging from 83% to 22%; with ypN stage being the most important single prognostic variable.

CONCLUSIONS

Pathological LN stage within the resection specimen was the single most important determiner of survival. Our results suggest that the assessment of regression changes within the primary tumour or LNs may not be necessary to define the prognosis further.

Primary results of the ICONIC phase 2 trial of perioperative FLOT plus avelumab (FLOT-A) in operable oesophagogastric adenocarcinoma (OGA)

446

Background: ICONIC evaluated 4+4 cycles of FLOT-A (2-weekly standard FLOT with 10mg/kg of the anti-PDL1 antibody avelumab) for perioperative treatment of early-stage OGA. We report R0 resection rates, pathologic complete response rates (pCR), pathologic tumour regression grades (TRG) according to Mandard classification and progression free survival (PFS) data in the modified intention to treat population (mITT), and translational analyses. Methods: ICONIC is a single-arm phase II trial of FLOT-A in patients (pts) with ≥cT2-4 or N+ OGA. The pCR rate in surgical specimens was the primary endpoint. Response evaluation according to Mandard, R0 rates and PFS were among secondary endpoints. PD-L1 expression was assessed according to the combined positive score (CPS) with the 22C3 pharmDx kit. Results: The trial closed early after the pCR rate was 15% (95% CI: 49%-83%) once 34 pts in the mITT population (defined as pts who had 1-4 cycles FLOT-A and surgery) as the pre-specified aim to demonstrate a pCR rate of 25% in 40 pts was unlikely to be met. Baseline characteristics of the mITT population were: median age 64y, 79% male, 79% OG junction, 6% oesophageal, 15% stomach, 65% poorly differentiated, 79% T3/4, 59% N+. 91% of pts received all 4 pre-operative cycles and 97% of pts achieved R0 resections. PDL1 CPS ≥1 and CPS ≥5 were nevertheless associated with increased TRG3 and decreased TRG4/5 rates. 3/34 pts (9%) had hypermutated/MMRd tumours and after their exclusion, the association of higher CPS with better TRG3 and decreased TRG4/5 remained. With a median follow up duration of 15.8 months the 12-month PFS was 93.1% (95% CI: 75.1%-98.2%) which is promising compared to historic results with peri-operative FLOT. Conclusions: Although FLOT-A failed to increase pCR rates to 25%, there is a trend towards higher TRG3 and lower TRG4/5 in pts with PDL1 CPS≥1 and CPS≥5 and promising PFS indicate activity of immunotherapy in combination with FLOT chemotherapy. Translational and biomarker analyses by exome- and RNA-sequencing, and multiplex immune cell staining are ongoing and will be reported. Clinical trial information: NCT03399071 . [Table: see text]

Impact of infiltrating T cell subtypes on survival and response to FLOT chemotherapy in resectable oesophagogastric adenocarcinoma (OGA)

443

Background: The prognostic and predictive relevance of tumour infiltrating T cell subtypes and of PD-L1 expression in localised OGA treated with FLOT chemotherapy (CTx) and surgery is poorly understood. Methods: Pre-CTx biopsy tissue was retrospectively collected from 46 patients (pts) with localised OGA who received perioperative FLOT and underwent surgery at a single institution. Opal Multicolour immunofluorescence was performed with primary antibodies against CD4, CD8, FOXP3, CD45RO, PD-1 and cytokeratin. Digital image analysis was performed using inForm and HALO softwares. PD-L1 CPS was determined using the E1L3N clone and the standard CPS assessment algorithm (CPS≥5 = high; CPS <5 = low). CTx responses were assessed according to Mandard Tumour Regression Grade (TRG). For each immune cell marker and T cell phenotype, high vs low groups were defined using median cell density (count/mm2) as the cut-off. Association of high vs low cell density with disease free survival (DFS) was assessed using the log-rank test and correlation with pathological response to CTx was assessed using the Chi-squared test. The paired Wilcoxon rank-sum test was used to compare differences in immune cell densities between paired pre-CTx biopsy and post-CTx resection samples in a subset of 35 pts. Results: Pts with a PD-1+ cell density above median in biopsy had significantly longer DFS compared to those with a density below median (median DFS not reached vs 1111 days; HR 0.3, 95% CI 0.1 – 0.8; p=0.028). A trend towards longer survival was also observed in the CD8+ high, FOXP3+ high, and activated CD8+ (CD8+ PD-1+) high groups. There was no association between PD-L1 CPS, CD4+, CD45RO+, memory CD8+ (CD8+ CD45RO+), regulatory CD4+ (CD4+ FOXP3+), memory CD4+ (CD4+ FOXP3- CD45RO+), and activated CD4+ (CD4+ FOXP3- PD-1+) cells and survival. Pts with higher density of PD-1+ cells achieved better responses than those with low PD-1+ cells (TRG1/2 48% vs 9%, p=0.017). Pts with PD-L1 CPS ≥10 in biopsy were numerically more likely to achieve better responses to FLOT (46% TRG1/2). PD1+ cell density decreased in resection specimens in good CTx responders but did not differ in non-responders. FOXP3+ cells significantly decreased whereas CD45RO+ cells and memory CD8+ cells significantly increased in non-responders only. Conclusions: These results indicate prognostic and predictive value of PD-1 expressing tumour infiltrating T cells in resectable OGA treated with perioperative FLOT CTx. CD8+, activated CD8+ and FOXP3+ cells were associated with a trend in longer survival. This analysis provides candidate biomarkers for further study in larger cohorts on the association between infiltrating immune cells and prognosis as well as response to standard cytotoxic CTx in Western patients.

Digital histological markers based on routine H&E slides to predict benefit from maintenance immunotherapy in esophagogastric adenocarcinoma

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Background: Immune checkpoint inhibition (ICI) is an effective treatment for a subset of patients with inoperable esophagogastric (EG) adenocarcinoma. Robust predictive biomarkers are required to identify these patients and a variety of strategies including immunohistochemical staining of PD-L1 and tumor mutational burden (TMB) assessment have been employed. Here, we explore digital histological (dHis) markers based on routine hematoxylin and eosin (H&E) slides alone or in combination with molecular markers (PD-L1 and TMB) as predictive biomarkers of benefit from maintenance immunotherapy in patients with inoperable EG adenocarcinoma. Methods: We developed a deep learning based algorithm to construct novel digital histological (dHis) markers by summarizing the statistics of all different types of nuclei present in the tumor tissue sections, their morphological features and their colocalization across each of the whole slide image. The dHis markers were then input into a decision-tree based approach to test for prognostic and predictive power alone or in combination with molecular markers. We assessed two cohorts of patients randomized to surveillance (n=38) or maintenance durvalumab (n=35) after 18 weeks of first-line platinum-based chemotherapy in the PLATFORM trial (NCT02678182) according to the 12-week progression-free rate. We measured the accuracy as the area under the receiver operating characteristics curve (AUROC) to determine the prognostic and predictive power of each marker set. We conducted a stratified 3-fold cross-validation, repeated 5 times and report the overall AUROC results. Results: Molecular markers alone yielded an AUROC of 0.5581±0.0939 on the surveillance arm, 0.6671±0.1479 on the treatment arm, and 0.6376±0.0958 for both the arms. Digital histological markers alone yielded an AUROC of 0.8952±0.0638, 0.8995±0.0719 and 0.8488±0.0700 on surveillance, immunotherapy and both arms, respectively. When using these two sets of markers together for both arms, molecular markers offered a limited improvement (around 0.02). Patients with TMB in the highest tertile were associated with lower likelihood of having progressive disease 12 weeks after randomization. Interestingly, dHis markers from morphology of connective and inflammatory nuclei were highly predictive for treatment benefit. Conclusions: Preliminary results suggest digital histological markers offer significant improvement over PD-L1 and TMB markers alone for predicting benefit from immunotherapy in EG adenocarcinoma with the added advantages of scalable, rapid, low-cost and objective quantification on routine histology sections. We are further validating their effectiveness on a larger cohort. Clinical trial information: NCT02678182.

Neoadjuvant and adjuvant multimodality therapies in resectable esophagogastric adenocarcinoma

Introduction: Gastric and esophageal adenocarcinoma is a leading cause of cancer-related death globally. Surgery is the cornerstone modality for cure where feasible. Clinical studies over the past two decades have provided evidence for the use of perioperative chemotherapy and chemoradiotherapy to improve patient outcomes. However, there remains no global consensus in the optimal use of these therapies.Areas covered: In this review, the authors summarize the latest evidence for perioperative multimodality therapy in resectable esophagogastric adenocarcinoma including the use of combination chemotherapy and targeted therapy containing regimens. In addition, the authors discuss some of the clinical and molecular biomarkers, such as PET imaging and microsatellite instability which can inform future practice and further clinical investigation.Expert opinion: A multimodal approach has been proven to improve survival outcomes over surgery alone. Whilst there is no global standard of care for multi-modality therapies in resectable OG cancer, clinical trials are refining the use of chemotherapy and radiotherapy in the neoadjuvant and adjuvant settings. Further investigation is on-going to further optimize therapy and the integration of molecular targeted agents.

Perioperative FLOT plus anti-PD-L1 avelumab (FLOT-A) in resectable oesophagogastric adenocarcinoma (OGA): Interim safety analysis results from the ICONIC trial

201

Background: ICONIC is a single-arm phase II trial investigating the safety and efficacy of perioperative FLOT-A in resectable OGA. Following a 3+3 design safety run-in phase, standard dose FLOT with 10mg/kg IV avelumab (dose level 0) q2weeks was taken forward into the main study. The aims of this pre-planned interim analysis were to assess perioperative safety and R0 resection rates. Methods: The interim analysis occurred once the 15th patient treated at dose level 0 reached 30 days post-surgery. Results: At data cut-off, 15 patients had received at least one cycle of FLOT-A and had undergone resection. The median age of patients was 63y (range: 25 – 73). 71% had an ECOG PS of 0. 60% of tumours were staged as T3 at baseline and 40% T2; 67% were N0, 7% N1 and 27% N2. Due to 5-FU related cardiac toxicity, two patients switched to alternative chemotherapy without 5-FU and avelumab. 13/15 patients (87%) completed 4 cycles of pre-operative FLOT-A; of these, five patients had avelumab omitted for one cycle for toxicity evaluation and management. 9/15 patients (60%) experienced a G3/4 adverse event (AE). These were FLOT-A-related in 8/15 patients (53.3%). The commonest G3/4 AEs were febrile neutropenia, neutropenia and diarrhoea. Median time from last chemotherapy to surgery was 6.4 weeks. No delays or failure to proceed to surgery occurred due to avelumab-related complications. 7% of patients had an American Society of Anaesthesiologists (ASA) preoperative risk score of I, 47% a score of II and 47% a score of III. 73% of patients had operations involving a thoracic approach (10 minimally invasive Ivor-Lewis oesophagogastrectomy with two field radical lymphadenectomy, 1 left thoracoabdominal oesophagogastrectomy and 4 gastrectomy with D2 lymphadenectomy). Median time to extubation was 6h (IQR: 4-24). The median Acute Physiology and Chronic Health Evaluation (APACHE) score at day 1 post-op was 12 (IQR: 10-15) with a median of 3 days (IQR: 2-4) of CCU care. No unexpected complications were reported intra-operatively or during post-operative recovery in FLOT-A treated patients. 5/14 evaluable patients at data cut-off (35.7%) had Clavien-Dindo grade II post-operative complications and 3/14 (21.4%) grade IIIa complications; of these 1 patient had an anastomotic leak that was treated endoscopically. There were no emergency re-operations. All 15 patients achieved R0 resections and were discharged home after a median of 13d (IQR: 11-16) in hospital. Conclusions: To date, FLOT-A has not led to unexpected or unusually severe perioperative complications in the context of major complex upper GI surgery for resectable OGA. Clinical trial information: NCT03399071.

Impact of sex and age on chemotherapy efficacy, toxicity and survival in localised oesophagogastric cancer: A pooled analysis of 3265 individual patient data from four large randomised trials (OE02, OE05, MAGIC and ST03)

BACKGROUND

There is a lack of large-scale randomised data evaluating the impact of sex and age in patients undergoing chemotherapy followed by potentially curative surgery for oesophagogastric cancer.

PATIENTS AND METHODS

Individual patient data from four prospective randomised controlled trials were pooled using a two-stage meta-analysis. For survival analysis, hazard ratios (HRs) were calculated for patients aged <70 and ≥ 70 years, as well as between males and females. Mandard tumour regression grade (TRG) and, ≥grade III toxicities were compared using logistic regression models to calculate odds ratios. All analyses were adjusted for the type of chemotherapy received.

RESULTS

3265 patients were included for survival analysis (2668 [82%] male, 597 [18%] female; 2627 (80%) <70 years, 638 (20%) ≥70 years). A significant improvement in overall survival (OS) (HR: 0.78; p < 0.001) and disease-specific survival (DSS) (HR: 0.78; p < 0.001) was observed in females compared with males. No significant differences in OS (HR: 1.11; p = 0.045) or DSS (HR: 1.01; p = 0.821) were observed in older patients compared with younger patients. For patients who underwent resection, older patients (15% vs 10%; p = 0.03) and female patients (14% vs 10%, p = 0.10) were more likely to achieve favourable Mandard TRG scores. Females experienced significantly more ≥grade III nausea (10% vs 5%; p≤0.001), vomiting (10% vs 4%; p≤0.001) and diarrhoea (9% vs 4%; p≤0.001) than males.

CONCLUSIONS

In this large pooled analysis using prospective randomised trial data, females had significantly improved survival while experiencing more gastrointestinal toxicities. Older patients achieved comparable survival to younger patients and thus, dependent on fitness, should be offered the same treatment paradigm.

Broadening the therapeutic horizon of advanced biliary tract cancer through molecular characterisation

Biliary tract cancers (BTC) comprise a group of rare and heterogeneous poor-prognosis tumours with the incidence of intrahepatic cholangiocarcinoma increasing over recent years. Combination chemotherapy with gemcitabine and cisplatin is the established first-line treatment for advanced BTC with a significant but modest survival advantage over monotherapy. There remains no accepted standard treatment in the second-line setting, although recent results from a randomised study have shown a survival benefit with 5-fluorouracil and oxaliplatin chemotherapy. Historically, clinical trials investigating targeted therapies in unselected BTC have failed to demonstrate significant clinical benefit. More recently, advancement in molecular exploration of BTC has shed light on the complex biological heterogeneity within these tumours and has also identified actionable genomic aberrations, such as fibroblast growth factor receptor 2 (FGFR2) gene fusions, isocitrate dehydrogenase (IDH) and BRAF mutations, which offer promise with the anticipation of increased responses and durable clinical benefit in selected patients. Several targeted drugs have now entered clinical development with some encouraging results being seen. Here we review the current and rapidly evolving therapeutic landscape of advanced BTC, including targeted therapies and immunotherapy. We also discuss how recent efforts and successes in BTC are overcoming the obstacles typically associated with precision medicine in rare cancers. Ultimately, the management of advanced BTC is likely to become molecularly selected in the near future with the hope of finally improving the bleak prognosis of patients with this disease.

Impact of age and sex on chemotherapy (CTx) efficacy, toxicity and survival in early oesophagogastric (OG) cancer: A pooled analysis of 3265 patients from four large randomised trials (OE02, OE05, MAGIC & ST03)

4022

Background: No large scale randomised data exists evaluating the impact of age and sex in patients (pts) undergoing potentially curative surgery and CTx for OG cancer. However, differences in age and sex may be contributing factors to variability in CTx dose-response and toxicity which could also impact survival. Methods: Data from four prospective randomised controlled trials were pooled using a two-stage meta-analysis. For survival data, hazard ratios were calculated for pts <70 and ≥70 years and between males and females. Pts were allocated to receive neoadjuvant platinum and fluoropyrimidine +/- anthracycline and bevacizumab. Mandard tumour regression grade (TRG) and prevalence of ≥G3 toxicities were compared according to the same subgroups using Chi-squared test. Results: 3265 pts were included for survival analysis (2668 (82%) M, 597 (18%) F; 2626 (80%) <70, 639 (20%) ≥70). A significant improvement in disease specific survival (DSS) (HR 0.78; p<0.001) and OS (HR 0.78; p<0.001) was observed in females vs males. Although OS was worse in older vs younger pts (HR 1.15; p=0.01) no significant difference in DSS was observed (HR 1.04; p=0.52). For those pts who underwent resection following neoadjuvant CTx, older patients (19 vs 13%; p=0.01) and female patients (19% vs 13%, p=0.02) were more likely to achieve more favourable Mandard TRG 1&2 scores. Older pts experienced significantly more ≥G3 neutropaenia (30 vs 22%; p=0.004). Females experienced significantly more ≥G3 nausea (12 vs 7%; p=0.006), vomiting (10 vs 5%; p≤0.001) and diarrhoea (9 vs 4%; p=0.001). Conclusions: This study represents the largest pooled analysis of age and sex differences on safety of neoadjuvant CTx and survival in early OG cancer. Females had significantly improved survival while experiencing more GI toxicities. Older pts achieved comparable DSS and thus, dependent on fitness, should be offered the same treatment paradigm as younger pts.

Cisplatin Substitution with Carboplatin During Radical Chemoradiotherapy for Oesophagogastric Carcinoma: Outcomes from a Tertiary Centre

BACKGROUND/AIM

Cisplatin-based radical chemoradiotherapy (CRT) is utilised in oesophagogastric (OG) cancer but the toxicity profile of cisplatin limits its use. This study aimed to evaluate the clinical characteristics and outcomes of patients treated with either cisplatin or carboplatin based CRT at our institution.

MATERIALS AND METHODS

This is a retrospective analysis of patients with localised OG cancer undergoing CRT with cisplatin/fluoropyrimidine (CX/F) or carboplatin/fluoropyrimidine (CarboX/F) between January 2001 and December 2014.

RESULTS

A total of 91 eligible patients were included. Median age was 65 years (IQR=57-75) for CX/F and 77 years (IQR=69-80) for CarboX/F. Adenocarcinoma histology and Charlson comorbidity index were higher in the CarboX/F group. Endoscopic complete response (CR) was achieved in 64% of CX/F group and 48% of CarboX/F group (p=0.19). The median PFS for CX/F was 31.0 months (95%CI=18.2-NE) vs. 18.7 months for CarboX/F (95%CI=13.5-30.4; HR=1.49, p=0.21).

CONCLUSION

Despite significant differences in baseline clinical characteristics, patients treated with carboplatin CRT demonstrated no significant difference in PFS or endoscopic CR rate, compared to those treated with cisplatin.

Survival Outcomes in Asymptomatic Patients With Normal Conventional Imaging but Raised Carcinoembryonic Antigen Levels in Colorectal Cancer Following Positron Emission Tomography-Computed Tomography Imaging

BACKGROUND

This study had two aims: (a) to evaluate the utility of fluorine 18-fluorodeoxyglucose (FDG) positron emission tomography (PET)-computed tomography (CT) in detecting occult disease recurrence with raised carcinoembryonic antigen (CEA) and (b) to establish the prognostic effects of early detection of disease recurrence in patients with colorectal cancer (CRC).

PATIENTS AND METHODS

Clinico-pathological data were obtained from all consecutive patients undergoing CRC surveillance from 2004 to 2010 who had an elevated CEA level (>3 ng/mL in nonsmokers, >5 ng/mL in smokers) but normal or equivocal conventional investigations. Histopathological confirmation or a minimum of 12 months' clinical and radiological follow-up were required to ascertain disease relapse.

RESULTS

A total of 1,200 patients were screened; of those, 88 (59% men; mean age, 66 years [SD, 9.6]) eligible patients (67 with normal and 21 with equivocal results on conventional investigations) were identified. Recurrent disease was detected in 56 of 88 patients (64%). The sensitivity of FDG PET-CT to detect recurrence was 49 of 56 (88%; 95% confidence interval [CI], 76%-95%) and specificity was 28 of 32 (88%; 95% CI, 71%-97%). Twenty-seven of 49 (55%) patients with PET-CT-detected relapsed disease were deemed eligible for further curative therapy; 19 (70%) went on to receive potentially curative therapy. The median time to progression (8.8 months [interquartile range (IQR), 4.5-19.1 months] vs. 2.2 months [IQR, 0.7-5.6]), median overall survival (39.9 months [IQR, 23.6-65.4 months] vs. 15.6 months [IQR, 7.3-25.7 months]), and 5-year survival (36.8% [95% CI, 16.5%-57.5%] vs. 6.1% [95% CI, 1.1%-17.6%]; p ≤ .001) were higher in patients who received potentially curative therapy than in those who received noncurative therapy.

CONCLUSION

FDG PET-CT is a highly sensitive and specific tool for the detection of occult CRC recurrence. In >50% of patients, recurrent disease may still be potentially amenable to curative therapy. Long-term survival can be achieved in such patients.

IMPLICATIONS FOR PRACTICE

Colorectal cancer (CRC) patients who, on follow-up, have normal or equivocal results on clinical investigations but raised carcinoembryonic antigen (CEA) levels pose a significant challenge to treating physicians. This study supported the notion that the early use of fluorodeoxyglucose (FDG) positron emission tomography (PET)-computed tomography (CT) may have predictive and prognostic value in management of such patients. Long-term disease control and cure can be achieved in a subgroup of this patient population with low-volume disease relapse who are amenable to potentially curative treatment strategies. Reassuringly, the sensitivity and specificity for recurrence did not significantly vary as a function of the CEA level, suggesting that even with a minimal CEA rise, benefit can be attained by conducting FDG PET-CT in a timely manner.