Immunotherapy in rectal cancer patients—a propensity score matched analysis of the National Cancer Database

Background Rectal cancer patients with microsatellite instability (MSI-H) are candidates for immunotherapy. However, there is little evidence on its effect on overall survival (OS). Methods Retrospective analysis of stage II–IV rectal adenocarcinoma patients in the National Cancer Database (NCDB) between 2010 and 2019. Propensity score matching was adjusted for baseline and treatment confounders. The cohort was divided into patients who received immunotherapy and matched controls. The primary outcome was OS. Results 5175/206,615 (2.5%) patients with rectal adenocarcinoma underwent immunotherapy. These patients were younger (58 vs 62 years; p