Multicenter retrospective study of prognostic impact of mismatch repair status in early-stage endometrial cancer treated with adjuvant radiation

A retrospective study at 11 US centers investigated the prognostic impact of mismatch repair (MMR) status among patients receiving adjuvant radiotherapy for early-stage endometrioid endometrial cancer. The study included 744 patients; 31.5% had dMMR status and 68.5% had pMMR status. At a median follow-up of 43.5 months, the overall survival and recurrence-free survival rates for the entire cohort were 92.5% and 84.9%, respectively. RFS was inferior for dMMR compared to pMMR (73.4% versus 88.6%), but no significant difference in OS was seen (90.8% versus 93.2%; p=0.5). On multivariable analysis, dMMR status was associated with worse RFS (HR 1.86; p=0.001), but not OS. The authors conclude that MMR status was independently associated with RFS but not OS among patients receiving adjuvant radiotherapy for early-stage endometrioïd endometrial cancer.