['To examine the role of radiotherapy (RT) in uterine leiomyosarcomas (LMS) and to determine the patient population who may benefit from RT.', 'From 1998-2008, 69 patients with primary uterine LMS underwent hysterectomy with or without pelvic radiotherapy to a median dose of 45 Gy. Univariate analysis was performed using the Kaplan-Meier method and cumulative-incidence function, and multivariate analyses using Fine and Gray or Cox proportional hazard models.', "Following surgery, 32 out of 69 patients received RT. There was no evidence of any correlation between patient, disease and treatment characteristics and the use of RT. Median follow-up was 57 months. RT was associated with reduced local recurrence (3y LR 19% vs. 39%; Gray's p\u2009=\u20090.019) and improved overall survival (3y OS 69% vs. 35%; log-rank p\u2009=\u20090.025) on univariate analysis. Multivariate analysis demonstrated that RT reduced LR (HR: 0.28, CI: 0.11-0.69, p\u2009=\u20090.006) and increased OS (HR: 0.44, CI: 0.23-0.85, p\u2009=\u20090.014) independent of other clinical and pathologic factors. Positive surgical margins increased the odds of LR (HR: 5.6, CI: 2.3-13.4, p\u2009=\u20090.00012). Large tumor size and advanced stage (II-IV) were associated with the development of distant metastases and inferior OS."] Does postoperative radiotherapy improve local control and survival in patients with uterine leiomyosarcoma?