P7 Is mismatch repair status prognostic of clinical outcomes in patients with early stage endometrioid endometrial cancer?

Loss of DNA mismatch repair (MMR) genes leads to microsatellite instability and promotes endometrial carcinogenesis. Several analyses have demonstrated that MMR deficiency among patients with early-stage endometrial cancer (EC) is associated with worse clinical outcomes. Pembrolizumab has clinical activity in patients with MMR-deficient tumors. The NRG-GY020 protocol seeks to investigate the addition of pembrolizumab to radiation (RT) in patients with early-stage high intermediate risk (HIR) EC with MMR deficiency. We aimed to assess these clinical outcomes in patients with early-stage endometrioid EC in relation to MMR status and risk of recurrence at a single institution.