Pan-cancer Transcriptomic Predictors of Perineural Invasion Improve Occult Histopathologic Detection

PURPOSE

Perineural invasion (PNI) is associated with aggressive tumor behavior, recurrence, and metastasis, and can influence the administration of adjuvant treatment. However, standard histopathologic examination has limited sensitivity in detecting PNI and does not provide insights into its mechanistic underpinnings.

EXPERIMENTAL DESIGN

A multivariate Cox regression was performed to validate associations between PNI and survival in 2,029 patients across 12 cancer types. Differential expression and gene set enrichment analysis were used to learn PNI-associated programs. Machine learning models were applied to build a PNI gene expression classifier. A blinded re-review of hematoxylin and eosin (H&E) slides by a board-certified pathologist helped determine whether the classifier could improve occult histopathologic detection of PNI.

RESULTS

PNI associated with both poor overall survival [HR, 1.73; 95% confidence interval (CI), 1.27-2.36; P < 0.001] and disease-free survival (HR, 1.79; 95% CI, 1.38-2.32; P < 0.001). Neural-like, prosurvival, and invasive programs were enriched in PNI-positive tumors (P _adj < 0.001). Although PNI-associated features likely reflect in part the increased presence of nerves, many differentially expressed genes mapped specifically to malignant cells from single-cell atlases. A PNI gene expression classifier was derived using random forest and evaluated as a tool for occult histopathologic detection. On a blinded H&E re-review of sections initially described as PNI negative, more specimens were reannotated as PNI positive in the high classifier score cohort compared with the low-scoring cohort (P = 0.03, Fisher exact test).

CONCLUSIONS

This study provides salient biological insights regarding PNI and demonstrates a role for gene expression classifiers to augment detection of histopathologic features.

Severe lymphopenia predicts poorer survival in patients with rectal cancer undergoing neoadjuvant chemoradiation

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Background: Chemoradiation (CRT) induced lymphopenia is common and associated with poorer survival in multiple solid malignancies. The objective of this study was to evaluate the prognostic impact of lymphopenia in patients with rectal cancer undergoing neoadjuvant CRT. We hypothesized that severe lymphopenia would correlate with worse survival. Methods: The inclusion criteria for this single-institution retrospective study were: 1) biopsy-proven diagnosis of rectal adenocarcinoma, 2) receipt of neoadjuvant CRT followed by surgery, and 3) absolute lymphocyte count (ALC) available prior to and within 12 weeks of CRT. In general, CRT consisted of 5-fluorouracil or capecitabine and RT with 50.4 Gy over 28 fractions. Lymphopenia was graded according to CTCAE v5.0. The primary variable of interest was ALC nadir within 12 weeks of CRT, dichotomized by ALC of < 0.5 k/μl (Grade 3 lymphopenia). The primary endpoint was overall survival (OS). Cox modeling and Kaplan-Meier methods were used to perform survival analyses. Results: 193 patients were identified. Median follow-up for the entire cohort was 68 months. Median age was 58. 62% were male, 82% were Caucasian, and 90% had ECOG ≤1. Median tumor distance from anal verge was 8 cm. Overall clinical stage was 1 or 2 in 23% and 3 in 77%. Median baseline CEA was 3.2 ng/ml. 83% received chemotherapy following RT. Following CRT, 70% underwent low anterior resection and 30% underwent abdominoperineal resection. Median baseline ALC for the entire cohort was 1.7 k/ul. ALC nadir within 12 weeks of initiating CRT was < 0.5 k/ul among 110 (57%) patients. Patients who developed severe lymphopenia with CRT had a lower baseline hemoglobin (median 13.3 vs. 14.0 g/dl, p = 0.022) and lower baseline ALC (median 1.6 vs. 1.8 k/ul, p = 0.010) compared to those who did not develop severe lymphopenia. There were no differences in disease and treatment characteristics between the two groups. On multivariable Cox model, severe lymphopenia was significantly associated with increased hazards of death (HR = 3.52 [95% CI 1.47-8.44], p = 0.005). Receipt of chemotherapy post-CRT (HR = 0.22 [95% CI 0.09-0.54], p = 0.001) predicted better OS while higher pathologic T (HR = 8.01 [95% CI 2.98-17.21], p < 0.001) and N stage (HR = 9.43 [95% CI 3.19-27.86], p < 0.001) and positive surgical margin (HR = 3.77 [95% CI 1.13-12.62], p = 0.031) predicted worse OS. The 5-year OS was 79% vs. 92% in the cohort with vs. without severe lymphopenia, respectively (log-rank p = 0.001). Conclusions: CRT-induced lymphopenia is common and severe lymphopenia may be a prognostic marker of poorer survival in rectal cancer. Closer observation in high-risk patients and treatment modifications may be potential approaches to mitigating CRT-induced lymphopenia. Our findings also suggest an important role of the host immunity in rectal cancer outcomes, supporting the ongoing efforts of immunotherapy trials in rectal cancer.

Prognostic impact of chemoradiation-related lymphopenia in patients with gastric and gastroesophageal cancer

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Background: Limited data exists on how chemoradiation (CRT)-induced lymphopenia affects survival outcomes in patients with gastric and gastroesophageal junction (GEJ) cancer. We evaluated the association between severe lymphopenia and its association with survival in gastric and GEJ cancer patients treated with CRT. We hypothesized that severe lymphopenia would be a poor prognostic factor. Methods: We performed a retrospective analysis of 154 patients with stage 1-3 gastric or GEJ cancer who underwent CRT at our institution. Patients underwent photon-based radiation therapy (RT) with a median dose of 50.4 Gy (IQR 45.0-50.4 Gy) over 28 fractions and concurrent chemotherapy (CTX) with carboplatin/paclitaxel, 5-fluorouracil based regimen, or capecitabine. 49% received CTX prior to RT. 84% underwent surgical resection, 57% pre-CRT and 26% post-CRT. Absolute lymphocyte count (ALC) at baseline and at 2 months since initiating RT were analyzed. Severe lymphopenia, defined as Grade 3 or worse lymphopenia (ALC < 0.5 k/μl), was analyzed for any association with overall survival (OS). Results: Median time of follow up was 48 months. Median age was 65. 77% were male and 86% were Caucasian. ECOG PS was 0 or 1 in 90% and 2 in 10%. Tumor location was stomach in 38% and GEJ in 62%. Timing of CRT was preoperative among 68% and postoperative among 32%. The median ALC at baseline for the entire cohort was 1.6 k/ul (range 0.3-7.0 k/ul). At 2 months post-CRT, 49 (32%) patients had severe lymphopenia. Patients with severe lymphopenia post-CRT had a slightly lower baseline TLC compared to patients without severe lymphopenia (median TLC 1.4 k/ul vs. 1.6 k/ul; p = 0.005). There were no differences in disease and treatment characteristics between the two groups. On the multivariable Cox model, severe lymphopenia post-CRT was significantly associated with increased risk of death (HR = 3.99 [95% CI 1.55-10.28], p = 0.004). ECOG PS 2 (HR = 34.97 [95% CI 2.08-587.73], p = 0.014) and postoperative CRT (HR = 5.55 [95% CI 1.29-23.86], p = 0.021) also predicted worse OS. The 4-year OS among patients with severe lymphopenia was 41% vs. 61% among patients with vs. without severe lymphopenia (log-rank test p = 0.041). Conclusions: Severe lymphopenia significantly correlated with poorer OS in patients with gastric or GEJ cancer treated with CRT. CRT-induced lymphopenia may be an important prognostic factor for survival in this patient population. Closer observation in high-risk patients and treatment modifications may be potential approaches to mitigating CRT-induced lymphopenia.

Prognostic impact of chemoradiation-related lymphopenia in patients with locally advanced pancreatic cancer

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Background: Chemoradiation (CRT) induced lymphopenia is common and associated with poorer survival in multiple solid malignancies. The objective of this study was to evaluate the prognostic impact of lymphopenia in patients with nonmetastatic, unresectable pancreatic ductal adenocarcinoma (PDAC) treated by neoadjuvant FOLFIRINOX (5-fluorouracil [5FU]/leucovorin/irinotecan/oxaliplatin) followed by CRT. We hypothesized that severe lymphopenia would correlate with worse survival. Methods: The inclusion criteria for this single-institution retrospective study were: 1) biopsy-proven diagnosis of unresectable PDAC, 2) absence of distant metastasis, 3) receipt of neoadjuvant FOLFIRINOX followed by CRT, and 4) absolute lymphocyte count (ALC) available prior to and two months after initiating CRT. In general, CRT consisted of 5FU or capecitabine and RT with 58.8 Gy over 28 fractions. Lymphopenia was graded according to CTCAE v5.0. The primary variable of interest was lymphopenia at two months, dichotomized by ALC of < 0.5/μl (Grade 3 lymphopenia). The primary endpoint was overall survival (OS). Cox modeling and Kaplan-Meier methods were used to perform survival analyses. Results: A total of 138 patients were identified. Median follow-up for the entire cohort was 16 months. Median age was 65. Fifty-six percent were female, 86% were Caucasian, and 97% had ECOG ≤1. Median tumor size was 3.8 cm. Tumor location was pancreatic head in 63%, body in 22%, tail in 8%, and neck in 7%. Median baseline ALC for the entire cohort was 1.5 k/ul. Two months after initiating CRT, 106 (77%) had severe (Grade 3 or worse) lymphopenia. While there were no significant differences in baseline patient or disease characteristics, patients with severe lymphopenia received higher doses of RT with longer duration of treatment compared to those without severe lymphopenia. On multivariable Cox model, severe lymphopenia at two months was significantly associated with increased hazards of death (HR = 4.00 [95% CI 2.03-7.89], p < 0.001). Greater number of neoadjuvant FOLFIRINOX cycles received prior to CRT was associated with lower hazards of death (HR = 0.84 [95% CI 0.77-0.92], p < 0.001). The 12-month OS was 73% vs. 90% in the cohort with vs. without severe lymphopenia, respectively (log-rank p < 0.001). Conclusions: Treatment-related lymphopenia is common and severe lymphopenia may be a prognostic marker of poorer survival in locally advanced pancreatic cancer. Closer observation in high-risk patients and minimization of RT dose and duration are potential approaches to mitigating CRT-related lymphopenia. Our findings also suggest an important role of the host immunity in pancreatic cancer outcomes, supporting the ongoing efforts of immunotherapy trials in pancreatic cancer.

Circulating Tumor DNA Predicts Pathologic and Clinical Outcomes Following Neoadjuvant Chemoradiation and Surgery for Patients With Locally Advanced Rectal Cancer

PURPOSE

This study was designed to assess the ability of perioperative circulating tumor DNA (ctDNA) to predict surgical outcome and recurrence following neoadjuvant chemoradiation for locally advanced rectal cancer (LARC).

MATERIALS AND METHODS

Twenty-nine patients with newly diagnosed LARC treated between January 2014 and February 2018 were enrolled. Patients received long-course neoadjuvant chemoradiation prior to surgery. Plasma ctDNA was collected at baseline, preoperatively, and postoperatively. Next-generation sequencing was used to identify mutations in the primary tumor, and mutation-specific droplet digital polymerase chain reaction was used to assess mutation fraction in ctDNA.

RESULTS

The median age was 54 years. The overall margin-negative, node-negative resection rate was 73% and was significantly higher among patients with undetectable preoperative ctDNA (n = 17, 88%) versus patients with detectable preoperative ctDNA (n = 9, 44%; P = .028). Undetectable ctDNA was also associated with more favorable neoadjuvant rectal scores (univariate linear regression, P = .029). Recurrence-free survival (RFS) was calculated for the subset (n = 19) who both underwent surgery and had postoperative ctDNA available. At a median follow-up of 20 months, patients with detectable postoperative ctDNA experienced poorer RFS (hazard ratio, 11.56; P = .007). All patients (4 of 4) with detectable postoperative ctDNA recurred (positive predictive value = 100%), whereas only 2 of 15 patients with undetectable ctDNA recurred (negative predictive value = 87%).

CONCLUSION

Among patients treated with neoadjuvant chemoradiation for LARC, patients with undetectable preoperative ctDNA were more likely to have a favorable surgical outcome as measured by the rate of margin-negative, node-negative resections and neoadjuvant rectal score. Furthermore, we have confirmed prior reports indicating that detectable postoperative ctDNA is associated with worse RFS. Future prospective study is needed to assess the potential for ctDNA to assist with personalizing treatment for LARC.

Impact of Treatment Sequencing on Survival for Patients with Locally Advanced Gastric Cancer

BACKGROUND

Data are limited concerning the survival outcomes of locally advanced gastric cancer patients according to the multimodality therapy (MMT) administered.

METHODS

Single institution, retrospective analysis of 235 patients with locally advanced gastric cancer from 2001 to 2015. All patients met criteria for curative-intent surgery and chemotherapy ± radiation therapy. Treatment regimens were: (1) surgery first with adjuvant chemoradiation therapy (S + Adj); (2) perioperative chemotherapy + surgery (Periop); and (3) total neoadjuvant therapy followed by surgery (TNT + S).

RESULTS

One hundred twenty-eight (60.0%) patients received S + Adj, 69 (26.8%) Periop, and 38 (13.2%) TNT + S. Of the 235 patients, 222 (94.5%) received surgery. All intended therapy was received by 81.6% of TNT + S, 44.5% of S + Adj, and 42.0% of Periop patients. MMT was significantly more likely to be completed by TNT + S patients (HR 6.67, p < 0.001). At a median follow-up of 37 months, survival rates on an intention-to-treat basis with TNT + S, Periop, and S + Adj were 52.6%, 59.4%, and 45.3%, respectively. Regimen and completion of MMT significantly affected overall mortality risk. Compared with Periop, TNT + S had similar mortality risk (hazard ratio [HR] 1.28, p = 0.421), whereas S + Adj had increased mortality risk (HR 1.64, p = 0.027).

CONCLUSIONS

The choice of treatment sequencing has a major impact on completion rates of multimodal therapy in patients with locally advanced gastric cancer. Less than 50% of patients treated with upfront surgery or perioperative chemotherapy receive all intended therapies. TNT has higher intended therapy completion rates and comparable survival compared with perioperative therapy in our data. Further prospective investigations of TNT are warranted.

Intraoperative Radiation Mitigates the Effect of Microscopically Positive Tumor Margins on Survival Among Pancreatic Adenocarcinoma Patients Treated with Neoadjuvant FOLFIRINOX and Chemoradiation

BACKGROUND

Microscopically positive margins (R1) negatively impact survival in pancreatic ductal adenocarcinoma (PDAC). For patients with close/positive margins, intraoperative radiotherapy (IORT) can improve local control. The prognostic impact of an R1 resection in patients who receive total neoadjuvant therapy (TNT; FOLFIRINOX with chemoradiation) and IORT is unknown.

METHODS

Clinicopathologic data were retrospectively collected for borderline/locally advanced (BR/LA) PDAC patients who received TNT and underwent resection between 2011 and 2019. Disease-free (DFS) and overall survival (OS) measured from time of diagnosis were compared between groups.

RESULTS

Two hundred one patients received TNT and were resected, with a median DFS and OS of 24 months and 47 months, respectively. Eighty-eight patients (44%) received IORT; of these, 69 (78%) underwent an R0 and 19 (22%) an R1 resection. There was no significant difference in clinicopathologic factors between the IORT and no-IORT groups, except for resectability status (LA: IORT 69%, no-IORT 53%, p = 0.021) and surgeons' concern for a positive/close margin. R1 resection was associated with worse DFS and OS in the no-IORT population. However, among patients who received IORT, there was no difference in DFS (R0: 29 months, IQR 14-47 vs R1: 20 months, IQR 15-28; p = 0.114) or OS (R0: 48 months, IQR 25-not reached vs R1: 37 months, IQR 30-47; p = 0.307) between patients who underwent R0 vs R1 resection. In multivariate analysis, within the IORT group, R1 resection was not associated with DFS or OS.

CONCLUSION

IORT may mitigate the adverse effect of an R1 resection on DFS and OS in BR/LA PDAC patients receiving TNT.

Radiation Therapy for Rectal Cancer: Executive Summary of an ASTRO Clinical Practice Guideline

PURPOSE

This guideline reviews the evidence and provides recommendations for the indications and appropriate technique and dose of neoadjuvant radiation therapy (RT) in the treatment of localized rectal cancer.

METHODS

The American Society for Radiation Oncology convened a task force to address 4 key questions focused on the use of RT in preoperative management of operable rectal cancer. These questions included the indications for neoadjuvant RT, identification of appropriate neoadjuvant regimens, indications for consideration of a nonoperative or local excision approach after chemoradiation, and appropriate treatment volumes and techniques. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

Neoadjuvant RT is recommended for patients with stage II-III rectal cancer, with either conventional fractionation with concurrent 5-FU or capecitabine or short-course RT. RT should be performed preoperatively rather than postoperatively. Omission of preoperative RT is conditionally recommended in selected patients with lower risk of locoregional recurrence. Addition of chemotherapy before or after chemoradiation or after short-course RT is conditionally recommended. Nonoperative management is conditionally recommended if a clinical complete response is achieved after neoadjuvant treatment in selected patients. Inclusion of the rectum and mesorectal, presacral, internal iliac, and obturator nodes in the clinical treatment volume is recommended. In addition, inclusion of external iliac nodes is conditionally recommended in patients with tumors invading an anterior organ or structure, and inclusion of inguinal and external iliac nodes is conditionally recommended in patients with tumors involving the anal canal.

CONCLUSIONS

Based on currently published data, the American Society for Radiation Oncology task force has proposed evidence-based recommendations regarding the use of RT for rectal cancer. Future studies will look to further personalize treatment recommendations to optimize treatment outcomes and quality of life.

Abstract PR-007: Single-nucleus and spatial transcriptomics of archival pancreatic ductal adenocarcinoma reveals multi-compartment reprogramming after neoadjuvant treatment

Molecular subtyping of pancreatic ductal adenocarcinoma (PDAC) remains in its nascent stages and does not currently inform clinical management or therapeutic development. Previously identified bulk expression subtypes in the untreated setting were influenced by contaminating stroma whereas single cell RNA-seq (scRNA-seq) of fresh tumors under-represented key cell types. Two consensus subtypes have arisen from these prior efforts: (1) classical-pancreatic, encompassing a spectrum of pancreatic lineage precursors, and (2) basal-like/squamous/quasi-mesenchymal, characterized by loss of endodermal identity and aberrations in chromatin modifiers. Basal-like tumors were associated with poorer responses to chemotherapy and worse survival in the metastatic setting but attempts to refine this binary classification have failed to further stratify patient survival. Recent clinical trials have supported the increasing adoption of neoadjuvant therapy to aggressively address the risk of micro-metastatic spread and to circumvent concerns of treatment tolerance in the postoperative setting. There is an urgent need to understand how preoperative treatment reprograms residual tumor cells to identify additional therapeutic vulnerabilities that can be exploited in combination with neoadjuvant CRT. Here, we developed a robust single-nucleus RNA-seq (snRNA-seq) technique for frozen archival PDAC specimens and used it to study both untreated tumors (n = 15) and those that received neoadjuvant CRT (n = 11). Gene expression programs learned across malignant cell and fibroblast profiles uncovered a clinically relevant molecular taxonomy with improved prognostic stratification (median survival: 11.2 months in highest risk group to 44.7 months in lowest risk group) compared to prior classifications. Moreover, in the neoadjuvant treatment context, there was lower expression of classical-like phenotypes in malignant cells in favor of basal-like phenotypes associated with TNF-NFkB and interferon signaling as well as the presence of novel acinar and neuroendocrine classical-like states, which may be more resilient to cytotoxic treatment. These results suggest that differentiated endodermal phenotypes are only prevalent enough to be detected under treatment selection pressure and when observed in treatment-naïve bulk studies, may reflect normal cell contamination. Spatially-resolved transcriptomics revealed an association between malignant cells expressing basal-like programs and higher immune infiltration with increased lymphocytic content, whereas those exhibiting classical-like programs were linked to sparser macrophage-predominant microniches, perhaps pointing to distinct therapeutic susceptibilities. Our refined molecular taxonomy and spatial resolution may help advance precision oncology in PDAC through informative stratification in clinical trials and insights into differential therapeutic targeting leveraging the immune system.

Citation Format: William L. Hwang, Karthik A. Jagadeesh, Jimmy A. Guo, Hannah I. Hoffman, Eugene Drokhlyansky, Nicholas Van Wittenberghe, Samouil Farhi, Denis Schapiro, Jason Reeves, Daniel R. Zollinger, George Eng, Jason M. Schenkel, William A. Freed-Pastor, Clifton Rodrigues, Domenic Abbondanza, Debora Ciprani, Jennifer Y. Wo, Theodore S. Hong, Andrew J. Aguirre, Orit Rozenblatt-Rosen, Mari Mino-Kenudson, Carlos Fernandez-del Castillo, Andrew S. Liss, Tyler E. Jacks, Aviv Regev. Single-nucleus and spatial transcriptomics of archival pancreatic ductal adenocarcinoma reveals multi-compartment reprogramming after neoadjuvant treatment [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2020 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2020;80(22 Suppl):Abstract nr PR-007.

Chemoradiation-Related Lymphopenia and Its Association with Survival in Patients with Squamous Cell Carcinoma of the Anal Canal

BACKGROUND

Although treatment-related lymphopenia (TRL) is common and associated with poorer survival in multiple solid malignancies, few data exist for anal cancer. We evaluated TRL and its association with survival in patients with anal cancer treated with chemoradiation (CRT).

MATERIALS AND METHODS

A retrospective analysis of 140 patients with nonmetastatic anal squamous cell carcinoma (SCC) treated with definitive CRT was performed. Total lymphocyte counts (TLC) at baseline and monthly intervals up to 12 months after initiating CRT were analyzed. Multivariable Cox regression analysis was performed to evaluate the association between overall survival (OS) and TRL, dichotomized by grade (G)4 TRL (<0.2k/μL) 2 months after initiating CRT. Kaplan-Meier and log-rank tests were used to compare OS between patients with versus without G4 TRL.

RESULTS

Median time of follow-up was 55 months. Prior to CRT, 95% of patients had a normal TLC (>1k/μL). Two months after initiating CRT, there was a median of 71% reduction in TLC from baseline and 84% of patients had TRL: 11% G1, 31% G2, 34% G3, and 8% G4. On multivariable Cox model, G4 TRL at two months was associated with a 3.7-fold increased risk of death. On log-rank test, the 5-year OS rate was 32% in the cohort with G4 TRL versus 86% in the cohort without G4 TRL.

CONCLUSION

TRL is common and may be another prognostic marker of OS in anal cancer patients treated with CRT. The association between TRL and OS suggests an important role of the host immunity in anal cancer outcomes.

IMPLICATIONS FOR PRACTICE

This is the first detailed report demonstrating that standard chemoradiation (CRT) commonly results in treatment-related lymphopenia (TRL), which may be associated with a poorer overall survival (OS) in patients with anal squamous cell carcinoma. The association between TRL and worse OS observed in this study supports the importance of host immunity in survival among patients with anal cancer. These findings encourage larger, prospective studies to further investigate TRL, its predictors, and its relationship with survival outcomes. Furthermore, the results of this study support ongoing efforts of clinical trials to investigate the potential role of immunotherapy in anal cancer.

Patterns of Failure and the Need for Biliary Intervention in Resected Biliary Tract Cancers After Chemoradiation

BACKGROUND

This study assessed patterns of failure and rates of subsequent biliary intervention among patients with resected biliary tract cancers (BTCs) including gallbladder carcinoma (GBC) and extra- and intrahepatic cholangiocarcinoma (eCCA and iCCA) treated with adjuvant chemoradiation therapy (CRT).

METHODS

In this single-institution retrospective analysis of 80 patients who had GBC (n = 29), eCCA (n = 43), or iCCA (n = 8) treated with curative-intent resection and adjuvant CRT from 2007 to 2017, the median radiation dose was 50.4 Gy (range 36-65 Gy) with concurrent 5-fluorouracil (5-FU) chemotherapy. All but two of the patients received adjuvant chemotherapy. The 2-year locoregional failure (LRF), 2-year recurrence-free survival (RFS), and 2-year overall survival (OS), and univariate predictors of LRF, RFS, and OS were calculated for the entire cohort and for a subgroup excluding patients with iCCA (n = 72). The predictors of biliary interventions also were assessed.

RESULTS

Of the 80 patients (median follow-up period, 30.5 months; median OS, 33.9 months), 54.4% had American Joint Committee on Cancer (AJCC) stage 1 or 2 disease, 57.1% were lymph node-positive, and 66.3% underwent margin-negative resection. For the entire cohort, 2-year LRF was 23.8%, 2-year RFS was  43.7%, and 2-year OS was 62.1%.  When patients with iCCA were excluded, the 2-year LRF was 22.6%, the 2-year RFS was 43.9%, and the 2-year OS was 59.2%. In the overall and subgroup univariate analyses, lymph node positivity was associated with greater LRF, whereas resection margin was not. Biliary intervention was required for 12 (63.2%) of the 19 patients with LRF versus 11 (18%) of the 61 patients without LRF (P < 0.001). Of the 12 patients with LRF who required biliary intervention, 4 died of biliary complications.

CONCLUSIONS

The LRF rates remained significant despite adjuvant CRT. Lymph node positivity may be associated with increased risk of LRF. Positive margins were not associated with greater LRF, suggesting that CRT may mitigate LRF risk for this group. An association between LRF and higher rates of subsequent biliary interventions was observed, which may yield significant morbidity. Novel strategies to decrease the rates of LRF should be considered.

Pancreatic ductal adenocarcinoma: tumour regression grading following neoadjuvant FOLFIRINOX and radiation

AIMS

In the adjuvant setting, when compared to gemcitabine, patients with pancreatic ductal adenocarcinoma (PDAC) treated with FOLFIRINOX (Folinic Acid, Fluorouracil, Irinotecan, and Oxaliplatin) show superior survival. In this study, we quantitatively assess the pathological tumour response to chemoradiation in pancreatectomy specimens and reassess guidelines for tumour regression grading.

METHODS AND RESULTS

We evaluated 92 patients with borderline resectable/locally advanced PDAC following pancreatectomy and neoadjuvant treatment with FOLFIRINOX and radiation. Demographic data, CAP tumour regression grade (TRG) and overall survival (OS) were recorded. A quantitative analysis of residual tumour was performed on the slide with the highest tumour burden to derive a tumour-to-tumour bed ratio. On univariate analysis, only lymph node status (P = 0.043) and CAP TRG (P = 0.038) correlated with OS. Sixteen per cent of patients showed a complete pathological response. The optimal tumour-to-tumour bed ratio cut-point was 11.6%, and on a multivariate model was the only pathological parameter that correlated with OS (P = 0.016) (hazard ratio = 2.27).

CONCLUSIONS

The high proportion of patients with PDAC showing complete and near-complete pathological responses supports the use of FOLFIRINOX and radiation in the neoadjuvant setting. Several traditional pathology parameters fail to predict OS in patients treated with chemoradiation, while a quantitative tumour-to-tumour bed ratio is a powerful predictor of OS. The data support a two-tiered approach to TRG based on tumour-to-tumour bed ratio, and quantitative analysis merits further consideration.

Refusal of surgery for colon cancer: Sociodemographic disparities and survival implications among US patients with resectable disease

BACKGROUND

We aimed to identify factors associated with refusal of surgery among patients with colon cancer.

METHODS

This 2004-2016 NCDB retrospective study identified AJCC stage I-III colon cancer patients who were recommended surgery. Multivariable logistic regression defined adjusted odds ratios of refusing treatment, with sociodemographic and clinical covariates. Treatment propensity-adjusted Cox proportional hazard ratios defined differential survival stratified by clinical stage, controlling for potential confounders.

RESULTS

Of 170,594 patients recommended surgery, 1116 refused. Increased rates of surgery refusal were associated with older age, African American race, CDCC>3, and female sex. Decreased rates of surgery refusal were associated with higher income and private insurance. Stratifying by stage, refusal rates among African Americans remained disparately high. Refusal of surgery was associated with worse overall survival.

CONCLUSIONS

Disparate rates of refusal of surgery for resectable colon cancer by race and other sociodemographic factors highlight potential treatment adherence reinforcement beneficiaries, necessitating further study of shared decision-making.

Impact of adjuvant therapy in patients with invasive intraductal papillary mucinous neoplasms of the pancreas

BACKGROUND

There is limited data on the efficacy of adjuvant therapy (AT) in patients with invasive intraductal papillary mucinous neoplasms of the pancreas (IPMN). This single center retrospective cohort study aims to assess the impact of AT on survival in these patients.

METHODS

Patients undergoing surgery for invasive IPMN between 1993 and 2018 were included in the study. We compared the clinicopathologic features and evaluated overall survival (OS) using multivariate Cox regression adjusting for adjuvant therapy, age, T and N stage, perineural and lymphovascular invasion. We also assessed survival differences between surgery alone and AT in node negative (N0) and node positive (N+) subgroups.

RESULTS

103 patients were included in the study; 69 underwent surgery alone while 34 also received AT. Patients in the AT group were significantly younger, presented at higher T and N stages and had more perineural and lymphovascular invasion. Median OS in the surgery alone group was 134 months and 65 months in the AT group, p = 0.052. On multivariate analysis, AT was not associated with improved OS; hazard ratio (HR) = 1.03 (0.52-2.05). In N0 patients, compared to surgery alone, AT was associated with a worse median OS (65 vs 167 months, p = 0.03), whereas in N+ patients there was a non-significant improvement (50.5 vs 20.4 months, p = 0.315).

CONCLUSION

AT did not improve survival in the overall cohort even after multivariate analysis. N0 patients have excellent survival, and AT should probably be avoided in them, whereas it may be considered in patients with N+ disease.

Dosimetric Analysis and Normal-Tissue Complication Probability Modeling of Child-Pugh Score and Albumin-Bilirubin Grade Increase After Hepatic Irradiation

PURPOSE

This study aimed to develop robust normal-tissue complication probability (NTCP) models for patients with hepatocellular carcinoma treated with radiation therapy (RT) using Child-Pugh (CP) score and albumin-bilirubin (ALBI) grade increase as endpoints for hepatic toxicity.

METHODS AND MATERIALS

Data from 108 patients with hepatocellular carcinoma treated with RT between 2008 and 2017 were evaluated, of which 47 patients (44%) were treated with proton RT. Of these patients, 29 received stereotactic body RT and 79 moderately hypofractionated RT to median physical tumor doses of 43 Gy in 5 fractions and 59 Gy in 15 fractions, respectively. A generalized Lyman-Kutcher-Berman (LKB) model was used to model the NTCP using 2 clinical endpoints, both evaluated at 3 months after RT: CP score increase of ≥2 and ALBI grade increase of ≥1 from the pre-RT baseline. Confidence intervals on LKB fit parameters were determined using bootstrap resampling.

RESULTS

Compared with previous NTCP models, this study found a stronger correlation between normal liver volume receiving low doses of radiation (5-10 Gy) and a CP score or ALBI grade increase. A CP score increase exhibited a stronger correlation to normal liver volumes irradiated than an ALBI grade increase. LKB models for CP increase found values for the volume-effect parameter of a = 0.06 for all patients, and a = 0.02/0.09 when fit to photon/proton patients separately. Subset analyses for patients with superior initial liver functions showed consistent dose-volume effects (a = 0.1) and consistent dose-response relationships.

CONCLUSIONS

This study presents an update of liver NTCP models in the era of modern RT techniques using relevant endpoints of hepatic toxicity, CP score and ALBI grade increase. The results show a stronger influence of low-dose bath on hepatic toxicity than those found in previous studies, indicating that RT techniques that minimize the low-dose bath may be beneficial for patients.

Serial ctDNA Monitoring to Predict Response to Systemic Therapy in Metastatic Gastrointestinal Cancers

PURPOSE

ctDNA offers a promising, noninvasive approach to monitor therapeutic efficacy in real-time. We explored whether the quantitative percent change in ctDNA early after therapy initiation can predict treatment response and progression-free survival (PFS) in patients with metastatic gastrointestinal cancer.

EXPERIMENTAL DESIGN

A total of 138 patients with metastatic gastrointestinal cancers and tumor profiling by next-generation sequencing had serial blood draws pretreatment and at scheduled intervals during therapy. ctDNA was assessed using individualized droplet digital PCR measuring the mutant allele fraction in plasma of mutations identified in tumor biopsies. ctDNA changes were correlated with tumor markers and radiographic response.

RESULTS

A total of 138 patients enrolled. A total of 101 patients were evaluable for ctDNA and 68 for tumor markers at 4 weeks. Percent change of ctDNA by 4 weeks predicted partial response (PR, P < 0.0001) and clinical benefit [CB: PR and stable disease (SD), P < 0.0001]. ctDNA decreased by 98% (median) and >30% for all PR patients. ctDNA change at 8 weeks, but not 2 weeks, also predicted CB (P < 0.0001). Four-week change in tumor markers also predicted response (P = 0.0026) and CB (P = 0.022). However, at a clinically relevant specificity threshold of 90%, 4-week ctDNA change more effectively predicted CB versus tumor markers, with a sensitivity of 60% versus 24%, respectively (P = 0.0109). Patients whose 4-week ctDNA decreased beyond this threshold (≥30% decrease) had a median PFS of 175 days versus 59.5 days (HR, 3.29; 95% CI, 1.55-7.00; P < 0.0001).

CONCLUSIONS

Serial ctDNA monitoring may provide early indication of response to systemic therapy in patients with metastatic gastrointestinal cancer prior to radiographic assessments and may outperform standard tumor markers, warranting further evaluation.

Total Neoadjuvant Therapy With FOLFIRINOX in Combination With Losartan Followed by Chemoradiotherapy for Locally Advanced Pancreatic Cancer: A Phase 2 Clinical Trial

Importance

Patients with locally advanced pancreatic cancer have historically poor outcomes. Evaluation of a total neoadjuvant approach is warranted.

Objective

To evaluate the margin-negative (R0) resection rate of neoadjuvant FOLFIRINOX (fluorouracil, leucovorin, oxaliplatin, and irinotecan) and losartan followed by chemoradiotherapy for locally advanced pancreatic cancer.

Design, Setting, and Participants

A single-arm phase 2 clinical trial was conducted at a large academic hospital from August 22, 2013, to May 22, 2018, among 49 patients with previously untreated locally advanced unresectable pancreatic cancer as determined by multidisciplinary review. Patients had Eastern Cooperative Oncology Group performance status 0 or 1 and adequate hematologic, renal, and hepatic function. Median follow-up for the analysis was 17.1 months (range, 5.0-53.7) among 27 patients still alive at study completion.

Interventions

Patients received FOLFIRINOX and losartan for 8 cycles. Patients with radiographically resectable tumor after chemotherapy received short-course chemoradiotherapy (5 GyE × 5 with protons) with capecitabine. Patients with persistent vascular involvement received long-course chemoradiotherapy (50.4 Gy with a vascular boost to 58.8 Gy) with fluorouracil or capecitabine.

Main Outcomes and Measures

R0 resection rate.

Results

Of the 49 patients (26 women and 23 men; median age 63 years [range, 42-78 years]), 39 completed 8 cycles of FOLFIRINOX and losartan; 10 patients had fewer than 8 cycles due to progression (5 patients), losartan intolerance (3 patients), and toxicity (2 patients). Seven patients (16%) had short-course chemoradiotherapy while 38 (84%) had long-course chemoradiotherapy. Forty-two (86%) patients underwent attempted surgery, with R0 resection achieved in 34 of 49 patients (69%; 95% CI, 55%-82%). Overall median progression-free survival was 17.5 months (95% CI: 13.9-22.7) and median overall survival was 31.4 months (95% CI, 18.1-38.5). Among patients who underwent resection, median progression-free survival was 21.3 months (95% CI, 16.6-28.2), and median overall survival was 33.0 months (95% CI, 31.4 to not reached).

Conclusions and Relevance

Total neoadjuvant therapy with FOLFIRINOX, losartan, and chemoradiotherapy provides downstaging of locally advanced pancreatic ductal adenocarcinoma and is associated with an R0 resection rate of 61%.

Trial Registration

ClinicalTrials.gov identifier: NCT01821729.

Proton beam radiotherapy for anal and rectal cancers

Gastrointestinal cancers are bordered by radiosensitive visceral organs, resulting in a narrow therapeutic window. The search for more efficacious and tolerable therapies raises the possibility that proton beam therapy's (PBT) physical and dosimetric differences from conventional therapy may be better suited to treat both primary and recurrent disease, which carries its own unique challenges. Currently, the maximal efficacy of radiation plans for primary and recurrent anorectal cancer is constrained by delivery techniques and modalities which must consider feasibility challenges and toxicity secondary to exposure of organs at risk (OARs). Studies using volumetric modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) demonstrate that more precise dose delivery to target volumes improves local control rates and reduces complications. By reducing the low-to-moderate radiation dose-bath to bone marrow, small and large bowel, and skin, PBT may offer an improved side-effect profile. The potential to reduce toxicity, increase patient compliance, minimize treatment breaks, and enable dose escalation or hypofractionation is appealing. In cases where prognosis is favorable, PBT may mitigate long-term morbidity such as secondary malignancies, femoral fractures, and small bowel obstruction.

Predictors of Resectability and Survival in Patients With Borderline and Locally Advanced Pancreatic Cancer who Underwent Neoadjuvant Treatment With FOLFIRINOX

OBJECTIVE

The aim of this study was to determine (1) whether preoperative factors can predict resectability of borderline resectable (BR) and locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC) after neoadjuvant FOLFIRINOX, (2) which patients might benefit from adjuvant therapy, and (3) survival differences between resected BR/LA patients who received neoadjuvant FOLFIRINOX and upfront resected patients.

BACKGROUND

Patients with BR/LA PDAC are often treated with FOLFIRINOX to obtain a margin-negative resection, yet selection of patients for resection remains challenging.

METHODS

Clinicopathologic data of PDAC patients surgically explored between 04/2011-11/2016 in a single institution were retrospectively collected.

RESULTS

Following neoadjuvant FOLFIRINOX, 141 patients were surgically explored (BR: 49%, LA: 51%) and 110 (78%) were resected. Resected patients had lower preoperative CA 19-9 levels (21 vs 40 U/mL, P = 0.03) and smaller tumors on preoperative computed tomography (CT) scan (2.3 vs 3.0 cm, P = 0.03), but no predictors of resectability were identified. Median overall survival (OS) was 34.2 months from diagnosis for all FOLFIRINOX patients and 37.7 months for resected patients. Among resected patients, preoperative CA 19-9 >100 U/mL and >8 months between diagnosis and surgery predicted a shorter postoperative disease-free survival (DFS); Charlson comorbidity index >1, preoperative CA 19-9 >100 U/mL and tumor size (>3.0 cm on CT or >2.5 cm on pathology) predicted decreased OS. DFS and OS were significantly better for BR/LA PDAC patients treated with neoadjuvant FOLFIRINOX compared with upfront resected patients (DFS: 29.1 vs 13.7, P < 0.001; OS: 37.7 vs 25.1 months from diagnosis, P = 0.01).

CONCLUSION

BR/LA PDAC patients with no progression on neoadjuvant FOLFIRINOX should be offered surgical exploration. Except size, traditional pathological parameters fail to predict survival among resected FOLFIRINOX patients. Resected FOLFIRINOX patients have survival that appears to be superior than that of resectable patients who go directly to surgery.

Hypofractionated Radiation Therapy for Unresectable/Locally Recurrent Intrahepatic Cholangiocarcinoma

OBJECTIVE

The aim of this study was to evaluate outcomes for patients with unresectable intrahepatic cholangiocarcinoma (ICC) treated with hypofractionated proton or photon radiation therapy (HF-RT).

METHODS

We retrospectively identified 66 patients with ICC who were treated with HF-RT from 2008 to 2018. Median age at RT was 76 years (range 30-92), including 27 patients (41%) aged ≥ 80 years. Median RT dose was 58.05 Gy (range 37.5-67.5), all delivered in 15 daily fractions. Thirty-two patients received proton RT and 34 patients received photon RT.

RESULTS

Median follow-up times from diagnosis and RT start were 21 months and 14 months, respectively. In total, five patients (7.6%) developed local failure. The 2-year outcomes were 84% local control (LC) and 58% OS. Among the 51 patients treated with definitive intent, the 2-year LC rate was 93% and the OS rate was 62%. On multivariate analysis for LC, older age was associated with a lower risk of local failure [hazard ratio (HR) 0.91; p = 0.02], while prior surgery (HR 16.5; p = 0.04) and macrovascular invasion (HR 123.93; p = 0.02) were independently associated with an increased risk of local failure. On multivariate analysis for OS, female sex (HR 0.33; p = 0.001) and prior chemotherapy (HR 0.38; p = 0.003) remained significantly associated with OS. On multivariate analysis for OS, compared with photon RT, there was a trend towards improved survival with proton RT (HR 0.50; p = 0.05). The rate of overall grade 3 + toxicity was 11%. One patient developed radiation-induced liver disease and was treated with corticosteroids.

CONCLUSIONS

HF-RT yields high rates of local control and is an effective modality to optimize biliary control for unresectable/locally recurrent ICC.