Primary resistance to immunotherapy in patients with a dMMR/MSI metastatic gastrointestinal cancer: who is at risk? An AGEO real-world study.

BACKGROUND: The outstanding efficacy of immunotherapy in metastatic dMMR/MSI gastro-intestinal (GI) cancers has led to a rapid increase in the number of patients treated. However, 20-30% of patients experience primary resistance to immune checkpoint inhibitors (ICIPR) and need better characterization. METHODS: This AGEO real-world study retrospectively analyzed the efficacy and safety of ICIs and identified clinical variables associated with ICIPR in patients with metastatic dMMR/MSI GI cancers treated with immunotherapy between 2015 and 2022. RESULTS: 399 patients were included, 284 with colorectal cancer (CRC) and 115 with non-CRC, mostly treated by an anti-PD(L)1 (88.0%). PFS at 24 months was 55.8% (95CI [50.8-61.2]) and OS at 48 months was 59.1% (95CI [53.0-65.9]). ORR was 51.0%, and 25.1% of patients were ICIPR. There was no statistical difference in ORR, DCR, PFS, or OS between CRC and non-CRC groups. In multivariable analysis, ICIPR was associated with ECOG-PS ≥ 2 (OR = 3.36), liver metastases (OR = 2.19), peritoneal metastases (OR = 2.00), ≥1 previous line of treatment (OR = 1.83), and age≤50 years old (OR = 1.76). CONCLUSION: These five clinical factors associated with primary resistance to ICIs should be considered by physicians to guide treatment choice in GI dMMR/MSI metastatic cancer patients.

Complete pathological response after chemotherapy or immune checkpoint inhibitors in deficient MMR metastatic colorectal cancer: Results of a retrospective multicenter study.

About 5% of the patients with metastatic colorectal cancers (mCRC) present microsatellite instability (MSI)/deficient mismatch repair system (dMMR). While metastasectomy is known to improve overall and progression-free survival in mCRC, specific results in selected patients with dMMR/MSI mCRC are lacking. Our study aimed to describe metastasectomy results, characterize histological response and evaluate pathological complete response (pCR) rate in patients with dMMR/MSI mCRC. We retrospectively reviewed data from all consecutive patients with dMMR/MSI mCRC who underwent surgical metastasectomy between January 2010 and June 2021 in 17 French centers. Primary outcome was to assess the pCR rate defined by tumor regression grade (TRG) 0. Secondary endpoints included relapse-free survival (RFS) and overall survival (OS), and explored TRG as predictive factor for RFS and OS. Among the 88 patients operated, 109 metastasectomies were performed in 81 patients after neoadjuvant treatment [chemotherapy ± targeted therapy (CTT): 69, 85.2%; immunotherapy (ICI): 12, 14.8%], and pCR was achieved in 13 (16.1%) patients. Among the latter, pCR rate were 10.2% in the patients having received CTT (N = 7) and 50.0% in the patients treated with ICI (N = 6). Radiological response did not predict TRG. With a median follow-up of 57.9 (IQR 34.2-81.6) months, median RFS was 20.2 (15.4-not reached) months, median OS was not reached. Major pathological responses (TRG0 + TRG1) were significantly associated with longer RFS (HR 0.12, 95% CI 0.03-0.55; P = .006). The pCR rate of 16.1% achieved with neoadjuvant treatment in patients with dMMR/MSI mCRC is consistent with previously reported rates in pMMR/MSS mCRC. Immunotherapy showed better pCR rate than chemotherapy ± targeted therapy. Further prospective trials are needed to validate immunotherapy as neoadjuvant treatment in resectable/potentially resectable dMMR/MSI mCRC and identify predictive factors for pCR.

BRAF V600E/RAS Mutations and Lynch Syndrome in Patients With MSI-H/dMMR Metastatic Colorectal Cancer Treated With Immune Checkpoint Inhibitors.

BACKGROUND: We pooled data from 2 cohorts of immune checkpoint inhibitors-treated microsatellite instability-high/mismatch repair-deficient (MSI/dMMR) metastatic colorectal cancer patients to evaluate the prognostic value of RAS/BRAFV600E mutations and Lynch syndrome (LS). PATIENTS AND METHODS: Patients were defined as LS-linked if germline mutation was detected and as sporadic if loss of MLH1/PMS2 expression with BRAFV600E mutation and/or MLH1 promoter hypermethylation, or biallelic somatic MMR genes mutations were found. Progression-free survival (PFS) and overall survival (OS) were adjusted on prognostic modifiers selected on unadjusted analysis (P < .2) if limited number of events. RESULTS: Of 466 included patients, 305 (65.4%) and 161 (34.5%) received, respectively, anti-PD1 alone and anti-PD1+anti-CTLA4 in the total population, 111 (24.0%) were treated in first-line; 129 (28.8%) were BRAFV600E-mutated and 153 (32.8%) RAS-mutated. Median follow-up was 20.9 months. In adjusted analysis of the whole population (PFS/OS events = 186/133), no associations with PFS and OS were observed for BRAFV600E-mutated (PFS HR= 1.20, P = .372; OS HR = 1.06, P = .811) and RAS-mutated patients (PFS HR = 0.93, P = .712, OS HR = 0.75, P = .202). In adjusted analysis in the Lynch/sporadic status-assigned population (n = 242; PFS/OS events = 80/54), LS-liked patients had an improved PFS compared to sporadic cases (HR = 0.49, P = .036). The adjusted HR for OS was 0.56 with no significance (P = .143). No adjustment on BRAFV600E mutation was done due to collinearity. CONCLUSION: In this cohort, RAS/BRAFV600E mutations were not associated with survival while LS conferred an improved PFS.

Consequences of the Hsp110DE9 mutation in tumorigenesis and the 5-fluorouracil-based chemotherapy response in Msh2-deficient mice.

Heat shock proteins (HSPs) play oncogenic roles in human tumours. We reported a somatic inactivating mutation of HSP110 (HSP110DE9) in mismatch repair-deficient (dMMR) cancers displaying microsatellite instability (MSI) but did not assess its impact. We evaluated the impact of the Hsp110DE9 mutation on tumour development and the chemotherapy response in a dMMR knock-in mouse model (Hsp110DE9KIMsh2KO mice). The effect of the Hsp110DE9 mutation on tumorigenesis and survival was evaluated in Msh2KO mice that were null (Hsp110wt), heterozygous (Hsp110DE9KI/+), or homozygous (Hsp110DE9KI/KI) for the Hsp110DE9 mutation by assessing tumoral syndrome (organomegaly index, tumour staging) and survival (Kaplan-Meier curves). 5-Fluorouracil (5-FU), which is the backbone of chemotherapy regimens in gastrointestinal cancers and is commonly used in other tumour types but is not effective against dMMR cells in vivo, was administered to Hsp110DE9KI/KI, Hsp110DE9KI/+, and Hsp110wtMsh2KO mice. Hsp110, Ki67 (proliferation marker) and activated caspase-3 (apoptosis marker) expression were assessed in normal and tumour tissue samples by western blotting, immunophenotyping and cell sorting. Hsp110wt expression was drastically reduced or totally lost in tumours from Msh2KOHsp110DE9KI/+ and Msh2KOHsp110DE9KI/KI mice. The Hsp110DE9 mutation did not affect overall survival or tumoral syndrome in Msh2KOHsp110DE9KI/+ and Msh2KOHsp110DE9KI/KI mice but drastically improved the 5-FU response in all cohorts (Msh2KOHsp110DE9KI/KI: P5fu = 0.001; Msh2KOHsp110DE9KI/+: P5fu = 0.005; Msh2KOHsp110wt: P5fu = 0.335). Histopathological examination and cell sorting analyses confirmed major hypersensitization to 5-FU-induced death of both Hsp110DE9KI/KI and Hsp110DE9KI/+ dMMR cancer cells. This study highlights how dMMR tumour cells adapt to HSP110 inactivation but become hypersensitive to 5-FU, suggesting Hsp110DE9 as a predictive factor of 5-FU efficacy.

Performance of Next-Generation Sequencing for the Detection of Microsatellite Instability in Colorectal Cancer With Deficient DNA Mismatch Repair.

BACKGROUND & AIMS: Next-generation sequencing (NGS) was recently approved by the United States Food and Drug Administration to detect microsatellite instability (MSI) arising from defective mismatch repair (dMMR) in patients with metastatic colorectal cancer (mCRC) before treatment with immune checkpoint inhibitors (ICI). In this study, we aimed to evaluate and improve the performance of NGS to identify MSI in CRC, especially dMMR mCRC treated with ICI. METHODS: CRC samples used in this post hoc study were reassessed centrally for MSI and dMMR status using the reference methods of pentaplex polymerase chain reaction and immunohistochemistry. Whole-exome sequencing (WES) was used to evaluate MSISensor, the Food and Drug Administration-approved and NGS-based method for assessment of MSI. This was performed in (1) a prospective, multicenter cohort of 102 patients with mCRC (C1; 25 dMMR/MSI, 24 treated with ICI) from clinical trials NCT02840604 and NCT033501260, (2) an independent retrospective, multicenter cohort of 113 patients (C2; 25 mCRC, 88 non-mCRC, all dMMR/MSI untreated with ICI), and (3) a publicly available series of 118 patients with CRC from The Cancer Genome Atlas (C3; 51 dMMR/MSI). A new NGS-based algorithm, namely MSICare, was developed. Its performance for assessment of MSI was compared with MSISensor in C1, C2, and C3 at the exome level or after downsampling sequencing data to the MSK-IMPACT gene panel. MSICare was validated in an additional retrospective, multicenter cohort (C4) of 152 patients with new CRC (137 dMMR/MSI) enriched in tumors deficient in MSH6 (n = 35) and PMS2 (n = 9) after targeted sequencing of samples with an optimized set of microsatellite markers (MSIDIAG). RESULTS: At the exome level, MSISensor was highly specific but failed to diagnose MSI in 16% of MSI/dMMR mCRC from C1 (4 of 25; sensitivity, 84%; 95% confidence interval [CI], 63.9%-95.5%), 32% of mCRC (8 of 25; sensitivity, 68%; 95% CI, 46.5%-85.1%), and 9.1% of non-mCRC from C2 (8 of 88; sensitivity, 90.9%; 95% CI, 82.9%-96%), and 9.8% of CRC from C3 (5 of 51; sensitivity, 90.2%; 95% CI, 78.6%-96.7%). Misdiagnosis included 4 mCRCs treated with ICI, of which 3 showed an overall response rate without progression at this date. At the exome level, reevaluation of the MSI genomic signal using MSICare detected 100% of cases with true MSI status among C1 and C2. Further validation of MSICare was obtained in CRC tumors from C3, with 96.1% concordance for MSI status. Whereas misdiagnosis with MSISensor even increased when analyzing downsampled WES data from C1 and C2 with microsatellite markers restricted to the MSK-IMPACT gene panel (sensitivity, 72.5%; 95% CI, 64.2%-79.7%), particularly in the MSH6-deficient setting, MSICare sensitivity and specificity remained optimal (100%). Similar results were obtained with MSICare after targeted NGS of tumors from C4 with the optimized microsatellite panel MSIDIAG (sensitivity, 99.3%; 95% CI, 96%-100%; specificity, 100%). CONCLUSIONS: In contrast to MSISensor, the new MSICare test we propose performs at least as efficiently as the reference method, MSI polymerase chain reaction, to detect MSI in CRC regardless of the defective MMR protein under both WES and targeted NGS conditions. We suggest MSICare may rapidly become a reference method for NGS-based testing of MSI in CRC, especially in mCRC, where accurate MSI status is required before the prescription of ICI.

Prognostic factors of BRAF V600E colorectal cancer with liver metastases: a retrospective multicentric study.

BACKGROUND: BRAF V600E-mutant colorectal cancers (CRCs) are associated with shorter survival than BRAF wild-type tumors. Therapeutic decision-making for colorectal liver metastases (CRLM) harboring this mutation remains difficult due to the scarce literature. The aim was to study a large cohort of BRAF V600E-mutant CRLM patients in order to see if surgery extend overall survival among others prognostic factors. METHODS: BRAF V600E-mutant CRCs diagnosed with liver-only metastases, resected or not, were retrospectively identified between April 2008 and December 2017, in 25 French centers. Clinical, molecular, pathological characteristics and treatment features were collected. Overall survival (OS) was defined as the time from CRLM diagnosis to death from any cause. Cox proportional hazard models were used for statistical analysis. RESULTS: Among the 105 patients included, 79 (75%) received chemotherapy, 18 (17%) underwent upfront CRLM surgery, and 8 (8%) received exclusive best supportive care. CRLM surgery was performed in 49 (46.7%) patients. CRLM were mainly synchronous (90%) with bilobar presentation (61%). The median OS was 34 months (range, 28.9-67.3 months) for resected patients and 10.6 (6.7-12.5) months for unresected patients (P < 0.0001). In multivariate analysis, primary tumor surgery (hazard ratio (HR) = 0.349; 95% confidence interval (CI) 0.164-0.744, P = 0.0064) and CRLM resection (HR = 0.169; 95% CI 0.082-0.348, P < 0.0001) were associated with significantly better OS. CONCLUSIONS: In the era of systemic cytotoxic chemotherapies, liver surgery seems to extend OS in BRAF V600E-mutant CRCs with liver only metastases historical cohort.

Adverse event load, onset, and maximum grade: A novel method of reporting adverse events in cancer clinical trials.

BACKGROUND: Current adverse event reporting practices do not document longitudinal characteristics of adverse effects, and alternative methods are not easily interpretable and have not been employed by clinical trials. Introducing time parameters in the evaluation of safety that are comprehensive yet easily interpretable could allow for a better understanding of treatment quality. In this study, we developed and applied a novel adverse event reporting method based on longitudinal adverse event changes to aid describing, summarizing, and presenting adverse event profile. We termed it the "Adverse Event Load, Onset, and Maximum Grade" method. METHODS: We developed two adverse event summary metrics to complement the traditional maximum grade report. Onset time indicates the time period in which the maximum grade for a specific adverse event occurred and was defined as "early" (i.e. maximum grade happened for the first time before 6 weeks) or "late" (i.e. after the 6th week). Adverse event load indicates the overall severity of a specific adverse event over the entire treatment. Higher adverse event load indicates a worse overall experience. These metrics can be calculated for adverse events with different maximum grades, in treatments with planned changes (e.g. dosage changes), using data sets with different number of adverse event data points between treatments (e.g. treatments with longer cycle lengths may have less adverse event data points) and on data sets with different adverse event data availability (e.g. cycle basis and patient-outcome reports). We tested the utility of this method using individual patient data from two major backbone therapies ("Irinotecan" and "Oxaliplatin") from the N9741 trial available in the Fondation ARCAD database (fondationarcad.org). We investigated profiles of diarrhea, neutropenia/leukopenia, and nausea/vomiting. RESULTS: Our method provided additional information compared to traditional adverse event reports. For example, for nausea/vomiting, while patients in Irinotecan had a higher risk of experiencing maximum grade 3-4 (15.6% vs 7.6%, respectively; p < 0.001), patients in both groups experienced similar severity over time (adverse effect load = 0.102 and 0.096, respectively; p = 0.26), suggesting that patients in Oxaliplatin experienced a lower-grade but more persistent nausea/vomiting. For neutropenia/leukopenia, more patients in Irinotecan experienced their maximum grade for the first time early in the treatment compared to patients in Oxaliplatin (67.9% vs 41.7%; p < 0.001), regardless of maximum grade. Longitudinal information can help compare treatments or guide clinicians on choosing appropriate interventions for low-grade but persistent adverse event or early adverse event onset. CONCLUSION: We developed an adverse event reporting method that provides clinically relevant information about treatment toxicity by incorporating two longitudinal adverse event metrics to the traditional maximum grade approach. Future research should establish clinical benchmarks for metrics included in this adverse event reporting method.

[Tumour deposition (TD), a probably underestimated poor prognostic criterion, to be taken into account in the therapeutic management of patients with stage III colon cancer]. / Les dépôts tumoraux (DT), un critère pronostique péjoratif probablement sous-estimé, à prendre en compte dans la prise en charge thérapeutique des malades atteints de cancer colique de stade III.

The management of colorectal cancer (CRC) relies heavily on TNM staging. In order to improve this staging, it is essential to identify all histological markers bearing a significant prognostic value. Among these, tumor deposits (TDs), defined as tumor foci in the pericolonic or perirectal adipose tissue with no residual lymph node tissue, have been shown to be associated with poor prognosis in cohort studies leading to their individualization in the TNM7 classification as pN1c. However, TDs are only considered in the absence of lymph node metastases. There is no consensus on this particular way of integrating TDs in the TNM classification. Indeed, at the time when the choice of the type of adjuvant treatment and its duration in stage III colon cancers (i.e. with lymph node metastases) is based on pT and pN criteria, taking into account TDs only in the absence of concomitant lymph node metastases is potentially responsible for a misclassification of some patients and wrong therapeutic decisions. In addition, many questions concerning the true definition of TDs, their origin, their prognostic value and the optimization of their consideration remain open. The objective of this review is to provide a synthesis of current knowledge on TDs in CRC, in view of their prognostic importance, their biological complexity and the scientific interest they are currently the subject of.

Prognosis and chemosensitivity of deficient MMR phenotype in patients with metastatic colorectal cancer: An AGEO retrospective multicenter study.

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 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.

Chemotherapy in Resected Neuroendocrine Carcinomas of the Digestive Tract: A National Study from the French Group of Endocrine Tumours.

BACKGROUND: Neuroendocrine carcinomas (NECs) of the digestive tract are rare and aggressive tumours. In localised disease the treatment is surgery. Based on expert consensus, international guidelines recommend the administration of adjuvant chemotherapy combining etoposide and platinum derivatives, justified by the high risk of metastatic relapse. However, no clinical study has proven the benefit of neoadjuvant or adjuvant chemotherapy. OBJECTIVES: We aimed to evaluate the effect of neoadjuvant +/- adjuvant and adjuvant therapy in this indication. METHODS: We performed a retrospective observational French study to evaluate overall survival (OS) and disease-free survival (DFS), prognostic factors for survival, and chemotherapy toxicity. RESULTS: Seventy-three patients had surgical resection of a localised digestive NEC between January 1, 2000 and December 31, 2016. The majority of patients presented colorectal (35%) tumours and the median Ki-67 value was 70%. Forty-three patients received chemotherapy, either perioperative (neoadjuvant +/- adjuvant) or adjuvant. The median OS and DFS for the whole population was 24 and 9 months, respectively. The median OS and DFS for patients receiving chemotherapy was 62 and 13 months, respectively. Positive postoperative node status and Ki-67 ≥80% had a negative prognostic impact on OS and DFS. Administration of chemotherapy had a positive prognostic impact on OS and DFS. Sixteen grade 3/4 toxicities were reported without toxic death. CONCLUSIONS: Our results suggest a positive effect on survival of chemotherapy in resected digestive NECs, but further studies are needed to confirm these results.

Characteristics of BRAFV600E Mutant, Deficient Mismatch Repair/Proficient Mismatch Repair, Metastatic Colorectal Cancer: A Multicenter Series of 287 Patients.

BACKGROUND: BRAFV600E mutations occurring in about 10% of metastatic colorectal cancers (mCRCs) are usually associated with a poor outcome. However, their prognostic factors are unknown. MATERIALS AND METHODS: We built a multicenter clinico-biological database gathering data from patients with BRAFV600E -mutant mCRC treated in one of the 16 French centers from 2006 to 2017. The primary endpoint was to identify prognostic factors using a Cox model. RESULTS: We included 287 patients (median age, 67 years [28-95]; female, 57%). Their median overall survival was 20.8 months (95% confidence interval [CI], 17.97-27.04), and median progression-free survival in the first-line setting was 4.34 months (95% CI, 3.81-5.03). Chemotherapy regimen and biological agents (antiangiogenic or anti-epidermal growth factor receptor) were not associated with overall and progression-free survival. Stage IV disease (synchronous metastases) and absence of curative-intent surgery were statistically associated with poor overall survival. Among the 194 patients with mismatch repair (MMR) status available, overall survival was significantly longer in patients with deficient MMR tumors compared with those with proficient MMR tumors (adjusted hazard ratio = 0.56; p = .009). CONCLUSION: Despite that BRAFV600E -mutant mCRCs are associated with poor overall and progression-free-survival, patients with deficient MMR tumors and/or resectable disease experienced a longer survival. These results highlight the importance of MMR testing and resectability discussion in patients with BRAFV600E mCRC in day-to-day practice. IMPLICATIONS FOR PRACTICE: Mismatch repair (MMR) testing and resectability discussion in patients with BRAFV600E metastatic colorectal cancer (mCRC) should be performed in day-to-day practice to steer treatment decision making in patients with BRAFV600E -mutant mCRC.

BRAF-Mutated Colorectal Cancer: What Is the Optimal Strategy for Treatment?

OPINION STATEMENT: The BRAF activating mutation, harbored by approximately 10% of colorectal cancers (CRC), confers dramatic prognosis to advanced diseases. In early-stage setting, the identification of the BRAF mutation does not impact the therapeutic decision. Yet, the BRAF mutation could be considered as a stratification factor in adjuvant trials, because of its prognostic impact after relapse. Moreover, both BRAF mutation and mismatch repair (MMR) statuses should be determined in all CRC to help identify sporadic tumors versus Lynch syndrome-related tumors. Indeed, in patients with MMR-deficient (dMMR) tumors and MLH1 loss of expression, the BRAFV600E mutation indicates a sporadic origin. In advanced BRAF-mutated CRC, the standard of care remains fluoropyrimidine-based cytotoxic regimen in combination with bevacizumab. Although a recent meta-analysis showed that there was insufficient data to justify the exclusion of anti-EGFR monoclonal antibodies, antiangiogenic agents should be preferred in the first-line setting. Despite the lack of a randomized phase 3 study dedicated to BRAF-mutated CRC, chemotherapy intensification combining a quadruple association of 5-fluorouracil, oxaliplatin, irinotecan (FOLFOXIRI), and bevacizumab seems like a valid option. Although first results with BRAF inhibitors as single agents in BRAF-mutated CRC were disappointing, their association with therapies targeting the MAPK pathway seems to overcome the primary resistance to BRAF inhibition. In the field of sporadic CRC, the BRAF mutation is strongly associated with MMR deficiency. Considering breakthrough results of immune checkpoint inhibitors in dMMR repair tumors, determination of the MMR status appears to be mandatory. Given the dramatic prognosis conferred by the BRAF mutation, patients with BRAF-mutated advanced CRC need to be systematically identified and proposed for clinical trial enrolment in order to benefit from innovative therapies.

[Immune response and digestive cancers: Prognostic and therapeutic implications]. / Réponse immune et cancers digestifs : implications pronostiques et thérapeutiques.

The aim of this article is to emphasize the impact of the immune response in digestive cancers, especially from colorectal (CRC) origin. In this setting, an adaptive lymphocytic infiltrate underlines the prognostic impact of the immune response, because it is associated to a favorable outcome. The next challenge will be to validate, in a prospective therapeutic trial, the integration of the immune response as decisional parameter for adjuvant therapy. The immune response is also a predictive parameter in microsatellite instable metastatic CRC, characterized by an adaptive lymphocytic infiltrate, leading to a very high response rate to immune therapies. However, prognostic and predictive biomarkers still need to be optimized in order to better select patients. These data are also valuable for digestive non-colorectal cancers, which are briefly analyzed. The methodology for the assessment of these prognostic and predictive biomarkers, which represents an important issue in precision medicine, is also discussed.

New Therapeutic Opportunities Based on DNA Mismatch Repair and BRAF Status in Metastatic Colorectal Cancer.

Recently, colorectal cancer (CRC) subtyping consortium identified four consensus molecular subtypes (CMS1-4). CMS1 is enriched for deficient mismatch repair (dMMR) and BRAF (V600E) tumors. Intriguingly, this subtype has better relapse-free survival but worse overall survival after relapse compared with the other subtypes. Growing evidence is accumulating on the benefit of specific therapeutic strategies such as immune checkpoint inhibition therapy in dMMR tumors and mitogen-activated protein kinase (MAPK) pathway targeted therapy in tumors harboring BRAF (V600E) mutation. After reviewing dMMR prognostic value, immune checkpoints as major targets for dMMR carcinomas will be highlighted. Following, BRAF (V600E) prognostic impact will be reviewed and therapeutic strategies with the combination of cytotoxic agents and especially the combinations of BRAF and MAPK inhibitors will be discussed.

Deficient mismatch repair/microsatellite unstable colorectal cancer: therapeutic advances and questions.

The microsatellite instability (MSI) phenotype is related to a deficiency of the DNA mismatch repair (dMMR) system and is observed in 5% of metastatic colorectal cancers (mCRCs). MSI/dMMR phenotype testing should be routine for all CRCs regardless of stage. Two complementary techniques with a high concordance (90-97%) allow us to determine the MSI/dMMR status of a tumor: immunohistochemistry and polymerase chain reaction. Since 2020 and the results of the phase III KEYNOTE 177 trial, pembrolizumab [anti-programmed cell death protein 1 (PD1)] is the new standard of care in first-line MSI/dMMR mCRC. To date, no combination of chemtotherapy ± targeted therapy with immune checkpoint inhibitors (ICIs) has been validated in the management of MSI/dMMR mCRC, and it is not known whether this combination would be beneficial. It is also unclear whether dual therapy with two ICIs is more effective than monotherapy. Several phase III trials are ongoing to answer these questions. Despite a high response rate and long-term benefit of a first line by anti-PD1, 30-50% of patients with MSI/dMMR mCRC experience an early or secondary progression. There are currently no validated predictive biomarkers of anti-PD1 ± anti-cytotoxic T lymphocyte antigen-4 resistance in patients with MSI/dMMR mCRC. In case of early progression on ICIs, the first two questions to consider are the possibility of pseudoprogression and the correct diagnosis of MSI/dMMR status. To date, there are no data on the use of adjuvant ICIs for MSI/dMMR resected colon cancers. By contrast, data are accumulating regarding the efficacy of neoadjuvant ICIs, with at least two-thirds of patients in the different trials in pathological complete response, making it possible to envisage 'Watch and wait' strategies in future.

Survival Outcomes in Patients with Monobloc-Resected Stage IIC (pT4bN0) Colon Cancer: A Retrospective Observational Cohort Study.

BACKGROUND: Stage II colon cancer (CC) exhibits considerable prognostic heterogeneous. Our objective was to assess survival but also the prognosis impact of microsatellite instability (MSI) in patients with stage IIC (T4bN0M0) CC. PATIENTS AND METHODS: We conducted a retrospective observational study including all patients who had primary stage IIC CC resection between 2010 and 2020 in 2 expert centers. The primary endpoint was overall survival (OS) and disease-free survival (DFS) and time-to-relapse (TTR) were secondary endpoints. RESULTS: Sixty-six patients, median age of 74 years [30-95], were included, with 37.9% presenting MSI (n = 25). Organ invasion involved the last ileal loop (n = 17), another colonic segment (n = 15), omentum (n = 13), visceral peritoneum (n = 13), and the bladder (n = 4). Surgical quality criteria showed complete monobloc resection in all patients and 93.9% R0 resection. After a median follow-up of 5 years [3.5-6.6], the entire population showed a 5-year OS of 65.2% [53.0-80.3] and 5-year DFS of 53.5% [41.1-69.6], with 18.9% [6.8-29.4] experiencing relapses at 5 years. The MSI phenotype correlated with improved 5-year OS (75.5% [56.5-100] vs. 59.5% [44.9-79.0], HR 0.41 [0.17-0.99]; P = .04), but DFS and TTR did not differ. Adjuvant chemotherapy was administered to 34.9% of patients. Univariate analysis identified age > 65 years, MSI status, and the number of nodes as factors associated with OS. CONCLUSION: These data underline, in relation to a low rate of relapse, the lack of consensus regarding the appropriate indication for adjuvant chemotherapy in this high-risk stage II population.

[An update on total neoadjuvant treatment of adenocarcinoma of the rectum]. / Actualisation des données sur le traitement néoadjuvant total de l'adénocarcinome du rectum.

A major advance has been made in the management of rectal cancer, with the emergence in 2021 of total neoadjuvant treatment. The main publications from the RAPIDO and PRODIGE-23 trials reported a significant improvement in progression-free survival and the pathological complete response rate. The aim of this review is to synthesize recent data on neoadjuvant treatment of rectal cancer, to explain the long-term results of the RAPIDO and PRODIGE-23 trials, and to put them into perspective, considering current advances in de-escalation strategies. The update of the 5-year survival data from the RAPIDO trial highlights an increased risk of loco-regional relapse, with 11.7% of relapses in the experimental group and 8.1% in the control group, while the update of the PRODIGE-23 trial confirms the benefits of this treatment regimen, with a significant improvement in overall survival. In addition, the results of the OPRA and PROPSPECT trials confirm the benefit of total neoadjuvant treatment with induction chemotherapy, as well as the possibility of surgical de-escalation in the OPRA trial and radiotherapy in the PROSPECT trial. The challenge for the future is to identify patients who require total neoadjuvant treatment with the aim of curative surgery to obtain a cure without local or distant relapse, and those for whom therapeutic de-escalation can be envisaged.

Non-metastatic colon cancer: French Intergroup Clinical Practice Guidelines for diagnosis, treatments, and follow-up (TNCD, SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, ACHBT, SFP, AFEF, and SFR).

INTRODUCTION: This article is a summary of the French intergroup guidelines regarding the management of non-metastatic colon cancer (CC), revised in November 2022. METHODS: These guidelines represent collaborative work of all French medical and surgical societies involved in the management of CC. Recommendations were graded in three categories (A, B, and C) according to the level of evidence found in the literature published up to November 2022. RESULTS: Initial evaluation of CC is based on clinical examination, colonoscopy, chest-abdomen-pelvis computed tomography (CT) scan, and carcinoembryonic antigen (CEA) assay. CC is usually managed by surgery and adjuvant treatment depending on the pathological findings. The use of adjuvant therapy remains a challenging question in stage II disease. For high-risk stage II CC, adjuvant chemotherapy must be discussed and fluoropyrimidine monotherapy or oxaliplatin-based chemotherapy proposed according to the type and number of poor prognostic features. Oxaliplatin-based chemotherapy (FOLFOX or CAPOX) is the current standard for adjuvant therapy of patients with stage III CC. However, these regimens are associated with significant oxaliplatin-induced neurotoxicity. The results of the recent IDEA study provide evidence that 3 months of treatment with CAPOX is as effective as 6 months of oxaliplatin-based therapy in patients with low-risk stage III CC (T1-3 and N1). A 6-month oxaliplatin-based therapy remains the standard of care for high-risk stage III CC (T4 and/or N2). For patients unfit for oxaliplatin, fluoropyrimidine monotherapy is recommended. CONCLUSION: French guidelines for non-metastatic CC management help to offer the best personalized therapeutic strategy in daily clinical practice. Each individual case must be discussed within a multidisciplinary tumor board and then the treatment option decided with the patient.

Efficacy of immune checkpoint inhibitors for metastatic colorectal cancer with microsatellite instability in second or latter line using synthetic control arms: A non-randomised evaluation.

PURPOSE: Immune checkpoint inhibitors (ICIs) appeared active in single-arm trials for patients with chemoresistant metastatic colorectal cancer (mCRC) harboring microsatellite instability (MSI). Given the paucity of randomised controlled trials (RCTs) in this setting, we evaluated the effect size of ICIs using intra-patients comparison and ARCAD database as historical controls. PATIENTS AND METHODS: Individual-patient data from NIPICOL and CheckMate 142 phase II trials that evaluated a combination of ICIs for MSI mCRC patients (N = 176) and from five non-ICI mCRC historical RCTs in second-line or latter (N = 4026) were analyzed. Firstly, promising of ICIs was identified using intra-patient comparison based on growth modulation index (GMI) defined the ratio of progression-free survivals (PFS) on ICIs and previous line of therapy. Survival outcomes of ICIs-treated patients were then compared with those matched non-ICIs treated from ARCAD database historical RCTs. RESULTS: Among ICIs-treated patients, median PFS on ICIs was 32.66 (range 0.10-74.25) versus 4.07 months (range 0.7-49.87) on prior therapy, resulting on median GMI of 4.97 (range 0.07-59.51; hazard-ratio (HR)= 0.16 (95 %CI=0.11-0.22, P < 0.001)). Compared to matched non-ICI patients, in third-line, median overall survival (OS) was not reached with ICIs versus 3.52 months with placebo (HR=0.20, 95 %CI=0.10-0.41, P < 0.001), and 6.51 months with active drugs (HR=0.30, 95 %CI=0.15-0.60, P = 0.001). In second-line, median OS was not reached with ICIs versus 11.7 months with chemotherapy+placebo (HR=0.12, 95 %CI=0.07-0.22, P < 0.001), and 16.3 months with chemotherapy+targeted therapy (HR=0.10, 95 %CI=0.05-0.19, P < 0.001). CONCLUSION: ICIs demonstrates high effect size for MSI mCRC patients in second-line and later. This work might be useful as an example of methodology to avoid RCTs when benefit from experimental therapy is likely to be high.

[A 2023 inventory in oncology news]. / Qu'est-ce que 2023 aura permis de changer dans nos pratiques en cancérologie ?

In 2023, the improvement of our therapeutic management has largely taken shape. The aim of our article is to highlight the major advances that will change our practices. These are not only in the field of treatment, but also in the improvement of supportive care. Here, we present these new developments organ by organ, cancer by cancer. You can read everything or concentrate on the cancers that are your areas of expertise. But this exhaustiveness should be representative of our current state of progress.