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.

Unresectable liver metastases in colorectal cancer: review of current strategies.

The objective of the treatment of colorectal cancer patients with unresectable liver metastases should be clearly defined at the outset. Potentially resectable patients should be distinguished from clearly unresectable patients. In defining resectability, it is important to take into account both anatomic characteristics and patient characteristic (comorbidities, symptoms, age). According to this evaluation, treatment should be tailored to each patient. The most widely accepted standard is doublet cytotoxic regimen plus biotherapy (anti-EGFR or anti-VEGF antibodies according to RAS status, but some patients could benefit from an intensified regimen, as triplet chemotherapy ± bevacizumab, or intraarterial treatments (hepatic arterial infusion, radioembolization or chemoembolization), in order to allow resectability. It is therefore very important to discuss the treatments with a multidisciplinary team, including an experienced surgeon, an interventional radiologist and an oncologist. On the other hand, some patients could benefit in terms of quality of life and decreased toxicity from less intense treatment when resection is not an objective. First-line monotherapy or a maintenance strategy with biotherapy and/or cytotoxics could be discussed with these patients, and treatment holidays should be considered in selected patients. Finally, in patients with secondary resection of liver metastases, specificity should be considered in choosing the best adjuvant treatment, such as response to preoperative treatment and individual risk of relapse, which many in some cases justify intensification with hepatic arterial infusion in an adjuvant setting.