The Role of Adjuvant Radiation in Uterine Sarcomas

Abstract

To determine clinical and pathological factors significant for overall survival (OS) and local-regional failure-free survival (LRFFS) in uterine sarcoma as they relate to adjuvant radiotherapy (AR). A retrospective analysis of 3,650 patients with uterine sarcoma was conducted using the National Oncology Database, a proprietary database of aggregated tumor registries owned by Impac Medical Systems (Sunnyvale, CA). Adjuvant radiotherapy was defined as postoperative external beam radiation to the pelvis, with or without brachytherapy. Prognostic factors were identified by multivariate analysis (MVA) using the Cox proportional hazards model. The Kaplan-Meier method was used to estimate survival, with significant differences (p < 0.05) determined using the log-rank test. The median follow-up time was 59 months, with a 5-year OS of 37%. Significant prognostic factors for OS were stage, race/ethnicity, grade, age, histology, lymph node status, and surgical treatment (p < 0.01 for all factors). Use of AR was not predictive for OS. For nonmetastatic cancer patients receiving definitive surgery (n = 2,206), the 5-year LRFFS was 87%. In this group, stage, grade, histology, and AR were prognostic for LRFFS (p < 0.05), with AR associated with improved outcome compared with surgery alone (hazard ratio = 0.4, p < 0.001). Patients with carcinosarcoma, endometrial stromal sarcoma, leiomyosarcoma, poorly differentiated tumors, and negative lymph nodes had reduced local-regional failure (LRF) with AR (log-rank, p < 0.05 for all). In the largest retrospective analysis of uterine sarcoma published thus far, AR conferred a 53% reduction in the risk of LRF at 5 years. Use of AR may have broader indications than what are currently accepted in clinical practice.