Consequences of a high incidence of microsatellite instability and BRAF-mutated tumors: A population-based cohort of metastatic colorectal cancer patients.

In unselected mCRC patients, MSI-H and mutBRAF cases were more common than previously reported. Patients with MSI-H tumors had worse survival, less benefit from chemotherapy, and they differed considerably from recent third-line immunotherapy trial patients as they were older and most had mutBRAF tumor (non-Lynch).