The role of radiation therapy in the treatment of Stage II endometrial cancer: A large database study

PURPOSE: The optimum adjuvant treatment for Stage II endometrial cancer patients is unknown. External beam radiation therapy (EBRT) is often considered the standard of care; however, retrospective series suggest that brachytherapy (BT) alone may be sufficient for selected patients. As randomized data are lacking, we used a large database to explore this question. METHODS AND MATERIALS: The National Cancer Data Base was queried for patients with pathologic International Federation of Gynecology and Obstetrics Stage II disease. Demographic, clinic-pathologic, and treatment details were compared between patients. Multivariable analysis was used to determine factors associated with receiving radiation therapy (RT). To account for imbalances between groups, a matched-pair analysis was completed. RESULTS: Eight thousand one hundred forty patients were included. RT was associated with overall survival (OS), with EBRT (hazard ratio [HR] 0.64), BT (HR 0.47), and combination (HR 0.54) showing increased OS on univariate analysis. Facility, urban location, diagnosis year, hysterectomy type, and chemotherapy did not reach significance. On multivariate analysis, RT was associated with OS, with EBRT (HR 0.69), BT (HR 0.60), and combination (HR 0.54) showing benefit. Using propensity-score matching, RT continued to show improved OS regardless of type: BT (82% vs. 73% 5-year OS) and EBRT (77% vs. 71%). BT as compared to EBRT had equivalent survival (81% vs. 79%, not statistically significant). CONCLUSION: This study of over 8,000 patients demonstrates that adjuvant RT confers a survival benefit in Stage II endometrial cancer and supports the continued use of RT in these patients. BT alone may be reasonable in carefully selected patients. 2018 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.