The role of adjuvant radiation in lymph node positive endometrial adenocarcinoma

The purpose of this study was to examine the impact of adjuvant radiation on overall survival (OS) and cancer specific survival (CSS) in patients with lymph node (LN) positive endometrial cancer.

We analyzed all women diagnosed with FIGO stage IIIC endometrial adenocarcinoma in the Surveillance, Epidemiology, and End Results database from 2004 to 2012 (n=2177). Patients not undergoing surgery or with missing treatment information were excluded. Chi-squared tests were used to compare predictors of treatment received. Cox proportional hazards model and Kaplan-Meier method were used to assess OS and CSS.

The median age was 60 (27-84) and the median follow-up was 31months (2-107). Adjuvant radiation was administered to 1248 (60.3%) patients. A total of 1363 (65.9%) patients had pelvic LN involvement while 658 (31.8%) had para-aortic involvement. The 3-year actuarial OS for patients with and without radiation was 80.5% and 67.6%, respectively (p<0.001). The 3-year actuarial CSS for patients with and without radiation was 83.4% and 73%, respectively (p<0.001). On multivariable analysis, receipt of radiotherapy remained associated with OS (HR 0.61 95% CI 0.51-0.74) and CSS (HR 0.65, 95% CI 0.53-0.80). After propensity matching, radiotherapy continued to be associated with an improved OS (HR 0.65 95% CI 0.54-0.78) and CSS (HR 0.65 95% CI 0.53-0.81). The addition of brachytherapy was not associated with OS or CSS.

In this large population registry analysis, adjuvant radiation was associated with improved OS and CSS in patients with LN positive endometrial cancer. Prospective data is needed to confirm these findings.