Dr. Bekaii-Saab on Microsatellite Instability in Colorectal Cancer

Tanios Bekaii-Saab, MD, professor of Medicine, Mayo Clinic, discusses microsatellite instability (MSI) in colorectal cancer.

The MSI group makes up about 4% of all patients with stage IV cancer. For those patients, studies suggest that using immunotherapies such as PD-1 inhibitors tend to induce significant responses that are both deep and durable, says Bekaii-Saab.

The question, though, is whether these PD-1 inhibitors would produce better outcomes than chemotherapy, or would add any benefit to chemotherapy in combination. If the research suggests that PD-1 inhibitors hold promising results in randomized trials in the first line, then it is likely that they will replace chemotherapy for MSI patients.