Background: The Immunoscore (IS), which prognostically classifies stage IeIII colon cancer (CC) patients, was evaluated in the International Duration Evaluation of Adjuvant Therapy (IDEA) France cohort study investigating 3 versus 6 months of oxaliplatin-based adjuvant chemotherapy in stage III CC patients. Patients and methods: Densities of CD3þ and CD8þ T cells in the tumor and invasive margin were determined by immunohistochemistry, quantified by digital pathology, and converted to IS. Mismatch repair status was determined by immunohistochemistry or by pentaplex PCR. Prediction of disease-free survival (DFS) by IS was analyzed by a multivariable Cox regression model in each study arm. Harrell's C-statistics were used to investigate the IS performance. Results: Samples of 1322 patients were available. IS Low, Intermediate (Int), and High were observed in 43.6%, 47.0%, and 9.4% of patients, respectively. IS Low identified patients at higher risk of relapse or death compared with Int þ High [hazard ratio (HR) ¼ 1.54; 95% confidence interval (CI) 1.24e1.93, P ¼ 0.0001]. The 3-year DFS was 66.80% (95% CI 62.23e70.94) for IS Low and 77.14% (95% CI 73.50e80.35) for IS Int þ High. In multivariable analysis, IS remained significantly independently associated with DFS (P ¼ 0.003) when adjusted for sex, histological grade, T/N stage, and microsatellite instability. For mFOLFOX6-treated patients (91.6% of the cohort), a statistical significant interaction was observed for the predictive value of IS for treatment duration (3 versus 6 months) in terms of DFS (P ¼ 0.057). IS Int þ High significantly predicted benefit of 6 months of treatment (HR ¼ 0.53; 95% CI 0.37e0.75; P ¼ 0.0004), including clinically low-and high-risk stage III CC (all P < 0.001). Conversely, patients with IS Low (46.4%) did not significantly benefit from the 6-month mFOLFOX6 versus the 3-month mFOLFOX6. Conclusions: The prognostic value of IS for DFS was confirmed in patients with stage III CC treated with oxaliplatinbased chemotherapy. Its predictive value for DFS benefit of longer duration of mFOLFOX6 adjuvant treatment was found in IS Int þ High. These results will be validated in an external independent cohort.

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Small bowel adenocarcinoma (SBA) is a rare tumour. We conducted a prospective cohort to describe the prevalence, survival and prognostic factors in unselected SBA patients. The study enrolled patients with all stages of newly diagnosed or recurrent SBA at 74 French centres between January 2009 and December 2012. In total, 347 patients were analysed; the median age was 63 years (range 23–90). The primary tumour was in the duodenum (60.6%), jejunum (20.7%) and ileum (18.7%). The prevalence of predisposing disease was 8.7%, 6.9%, 1.7%, 1.7% and 0.6% for Crohn disease, Lynch syndrome, familial adenomatous polyposis, celiac disease and Peutz‐Jeghers syndrome, respectively. At diagnosis, 58.9%, 5.5% and 35.6% of patients had localised and resectable, locally advanced unresectable and metastatic disease, respectively. Crohn disease was significantly associated with younger age, poor differentiation and ileum location, whereas Lynch syndrome with younger age, poor differentiation, early stage and duodenum location. Adjuvant chemotherapy (oxaliplatin‐based in 89.9%) was performed in 61.5% of patients with locally resected tumours. With a 54‐months median follow‐up, the 5‐year overall survival (OS) was 87.9%, 78.2% and 55.5% in Stages I, II and III, respectively. The median OS of patients with Stage IV was 12.7 months. In patients with resected tumours, poor differentiation (p = 0.047) and T4 stage (p = 0.001) were associated with a higher risk of death. In conclusion, our study showed that the prognosis of advanced SBA remains poor. Tumour characteristics differed according to predisposing disease. In SBA‐resected tumours, the prognostic factors for OS were grade and T stage.

PURPOSE In patients with resectable gastric/gastroesophageal junction (GEJ) adenocarcinoma, surgery plus perioperative platinum-based chemotherapy is the standard of care. Perioperative chemotherapy remains debatable for gastric/GEJ adenocarcinoma with deficient mismatch repair (dMMR)/microsatellite instability-high (MSI-H). PATIENTS AND METHODS NEONIPIGA (ClinicalTrials.gov identifier: NCT04006262 ) phase II study evaluated neoadjuvant nivolumab 240 mg once every two weeks ×6 and ipilimumab 1 mg/kg once every six weeks ×2, followed by surgery and adjuvant nivolumab 480 mg once every four weeks (nine injections) in patients with locally advanced resectable dMMR/MSI-H, clinical (c) tumor (T)2-T4 node (N)x metastasis (M)0 gastric/GEJ adenocarcinoma. The primary end point was a pathological complete response (pCR) rate. RESULTS Between October 2019 and June 2021, 32 patients with dMMR/MSI-H gastric/GEJ adenocarcinoma were enrolled. The median age was 65.5 years (range, 40-80). Clinical stages were cT2-T3N0 (n = 9), cT2-T3N1 (n = 22), and cT3N1M1 (n = 1, wrongly included). With a median follow-up of 14.9 months (95% CI, 10.6 to 17.6), 32 patients received neoadjuvant immunotherapy (27 patients completed all cycles). Neoadjuvant therapy-related grade 3/4 adverse events occurred in six patients (19%). Twenty-nine patients underwent surgery; three did not have surgery and had complete endoscopic response with tumor-free biopsies and a normal computed tomography scan (two refused surgery and one had metastasis at inclusion). The rate of surgical morbidity (Clavien-Dindo classification) was 55% (one postoperative death occurred). All 29 patients had an R0 resection, and 17 (58.6%; 90% CI, 41.8 to 74.1) had pCR (pathological T0N0). Becker tumor regression grades 1a, 1b, 2, and 3 were observed in 17 patients, three (including two pathological T0N1), two, and seven patients, respectively. Of the 29 patients with surgery, 23 received adjuvant nivolumab. At database lock, no patient had relapse and one died without relapse. CONCLUSION Nivolumab and ipilimumab-based neoadjuvant therapy is feasible and associated with no unexpected toxicity and a high pCR rate in patients with dMMR/MSI-H resectable gastric/GEJ adenocarcinoma.

Small bowel adenocarcinoma (SBA) is a rare tumour. Large genomic analyses with prognostic assessments are lacking. The NADEGE cohort has enrolled 347 patients with all stage SBA from 2009 to 2012. Next‐generation sequencing investigates the presence of 740 hotspot somatic mutations in a panel of 46 genes involved in carcinogenesis. The mismatch repair (MMR) status was assessed by immunochemistry. We have collected 196 tumour samples and 125 had conclusive results for mutation analysis. The number of mutations was 0 in 9.6% of tumours, only 1 in 32.0%, 2 in 26.4% and ≥3 in 32.0%. Overall, at least one genomic alteration was observed in 90.4% of tumour. The most frequent genomic alteration was in KRAS (44.0%), TP53 (38.4%), PIK3CA (20.0%), APC (18.4%), SMAD4 (14.4%) and ERBB2 (7.2%) genes. KRAS mutations were more frequent in synchronous metastatic tumours than in localised tumours (72.7% vs 38.2%, P = .003). There was no significant difference in the mutation rates according to primary location for the most frequently altered gene. ATM, FGFR3 and FGFR1 gene alterations were associated with Lynch syndrome and IDH1 mutations with Crohn disease. dMMR tumours were associated with younger age, localised tumours, less KRAS but more SMARCB1 mutations. No genomic alteration was associated with overall survival. There is a trend for better survival in patient with dMMR tumours. In conclusion, there is a different genomic alteration profile in SBA according to predisposing diseases. No association between genomic alterations and prognoses was observed except for a trend of better prognoses associated with dMMR.

Mismatch repair-deficient (dMMR) and/or microsatellite instability-high (MSI) colorectal cancers (CRC) represent about 5% of metastatic CRC (mCRC). Prognosis and chemosensitivity of dMMR/MSI mCRC remain unclear. This multicenter study included consecutive patients with dMMR/MSI mCRC from 2007 to 2017. The primary endpoint was the progression-free survival (PFS) in a population receiving first-line chemotherapy. Associations between chemotherapy regimen and survival were evaluated using a Cox regression model and inverse of probability of treatment weighting (IPTW) methodology in order to limit potential biases. Overall, 342 patients with dMMR/MSI mCRC were included. Median PFS and overall survival (OS) on first-line chemotherapy were 6.0 and 26.3 months, respectively. For second-line chemotherapy, median PFS and OS were 4.4 and 21.6 months. Longer PFS (8.1 vs. 5.4 months, p = 0.0405) and OS (35.1 vs. 24.4 months, p = 0.0747) were observed for irinotecan-based chemotherapy compared to oxaliplatin-based chemotherapy. The association was no longer statistically Additional Supporting Information may be found in the online version of this article. ratio; ICI: immune checkpoint inhibitors; IHC: immunohistochemistry; IPTW: inverse of probability of treatment weighting; mCRC: metastatic CRC; MSI: microsatellite instability; OS: overall survival; PFS: progression-free survival; pMMR: proficient mismatch repair; RR: response rate Tumor Markers and Signatures significant using IPTW methodology. In multivariable analysis, anti-VEGF as compared to anti-EGFR was associated with a trend to longer OS (HR = 1.78, 95% CI 1.00-3.19, p = 0.0518), whatever the backbone chemotherapy used. Our study shows that dMMR/MSI mCRC patients experienced short PFS with first-line chemotherapy with or without targeted therapy. OS was not different according to the chemotherapy regimen used, but a trend to better OS was observed with anti-VEGF. Our study provides some historical results concerning chemotherapy in dMMR/MSI mCRC in light of the recent nonrandomized trials with immune checkpoint inhibitors.What's new? Some reports suggest short overall survival (OS) and chemoresistance of mismatch repair-deficient and/or microsatellite instability-high metastatic colorectal cancers (dMMR/MSI mCRC). In a large multicenter series of dMMR/MSI mCRC we observed a relatively long OS but short progression-free survival. Irinotecan-based chemotherapy was not associated with better OS than oxaliplatin-based chemotherapy but anti-VEGF, as compared to anti-EGFR, was associated with a trend to longer OS. These results could help clinicians to choose treatment in patients with dMMR/MSI mCRC.

Purpose: Circulating tumor DNA (ctDNA) has been suggested as a major prognostic factor in resected stage-III colon cancer. We analyzed ctDNA of patients randomized in the phase III IDEA-France trial. Experimental Design: ctDNA was tested for WIF1 and NPY by droplet digital PCR with method developed and validated for colorectal cancer. Disease-free survival (DFS) and overall survival (OS) were analyzed via multivariable analysis in patients with ctDNA samples and in sub-groups according to treatment duration (3/6 months) and disease stage (high/low-risk stage III). Results: Of 2,010 randomized patients, 1,345 had available ctDNA samples (1,017 collected both post-surgery and pre-chemotherapy). More Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 (78% versus 69%) and T4 and/or N2 (40% versus 36%) were observed in patients studied (n = 1017) versus not analyzed (n = 993). There were 877 ctDNA-negative (86.2%) and 140 ctDNA-positive (13.8%) patients; their baseline characteristics were similar. With a median follow-up of 6.6 years, the 3-year DFS rate was 66.39% for ctDNA-positive patients and 76.71% for ctDNA-negative patients (P = 0.015). ctDNA was confirmed as an independent prognostic marker for DFS (adjusted HR = 1.55, 95% CI 1.13–2.12, P = 0.006) and OS (HR = 1.65, 95% CI 1.12–2.43, P = 0.011). ctDNA was prognostic in patients treated for 3 months and with T4 and/or N2 tumors, but not in those treated for 6 months and with T1–3/N1 tumors. Conclusions: In this first ctDNA assessment of a large series of patients with stage III colon cancer enrolled in phase III trial, post-surgery ctDNA was found in 13.8% of them and was confirmed as an independent prognostic marker. See related commentary by Bent and Kopetz, p. 5449

PURPOSE Tumor deposits (TDs) seem to affect the prognosis of patients with colon cancer (CC). In the seventh edition of the American Joint Committee on Cancer TNM staging system for CC, the presence of TDs is only considered in the absence of lymph node metastases (LNMs). In the era of personalized duration of histopathologic criteria-based adjuvant therapy, this could potentially lead to a decrease in the prognostic prediction accuracy. PATIENTS AND METHODS A post hoc analysis of all pathologic reports from patients with stage III CC included in the IDEA France phase III study (ClinicalTrials.gov identifier: NCT00958737 ) investigating the duration of adjuvant fluorouracil, leucovorin, and oxaliplatin or capecitabine and oxaliplatin therapy (3 v 6 months) was performed. The primary objective was to determine the prognostic impact of TD on disease-free survival (DFS). The effect of the addition of TD to LNM count on pN restaging was also evaluated. A multivariable analysis was performed to establish the association between TD and DFS. RESULTS Of 1,942 patients, 184 (9.5%) had TDs. The pN1a/b and pN1c populations showed similar DFS. TD-positive patients had worse prognosis compared with TD-negative patients, with 3-year DFS rates of 65.6% (95% CI, 58.0% to 72.1%) and 74.7% (95% CI, 72.6% to 76.7%; P = .0079), respectively. On multivariable analysis, TDs were associated with a higher risk of recurrence or death (hazard ratio [HR], 1.36; P = .0201). Other adverse factors included pT4 and/or pN2 disease (HR, 2.21; P < .001), the 3 months of adjuvant treatment (HR, 1.29; P = .0029), tumor obstruction (HR, 1.28; P = .0233), and male sex (HR, 1.24; P = .0151). Patients restaged as having pN2 disease (n = 35, 2.3%) had similar DFS as patients initially classified as pN2. CONCLUSION The presence of TDs is an independent prognostic factor for DFS in patients with stage III CC. The addition of TD to LNM may help to better define the duration of adjuvant therapy.