Tougeron D, Sueur B, Zaanan A, et al. - By performing this multicenter study with consecutive patients with dMMR (mismatch repair-deficient)/MSI (microsatellite instability-high) metastatic colorectal cancers (CRC) [mCRC] from 2007 to 2017, researchers intended to clarify prognosis as well as chemosensitivity of dMMR/MSI mCRC. In a population on first-line chemotherapy, progression-free survival (PFS) was assessed (primary endpoint). This analysis involved 342 patients with dMMR/MSI mCRC. On first-line chemotherapy, median PFS and overall survival (OS) were estimated to be 6.0 and 26.3 months, respectively, and these were 4.4 and 21.6 months, respectively, for second-line chemotherapy. In dMMR/MSI mCRC patients, short PFS was observed with first-line chemotherapy with or without targeted therapy. No difference was evident in OS according to the chemotherapy regimen employed, but antivascular endothelial growth factor was associated with a trend to better OS. This work affords some historical results regarding chemotherapy in dMMR/MSI mCRC considering recent nonrandomized trials with immune checkpoint inhibitors.