Radiotherapy and extent of surgical resection in retroperitoneal soft-tissue sarcoma: Multi-institutional analysis of 261 patients

Background and Objective To examine the impact of adjuvant radiotherapy (RT) and surgical technique on survival in retroperitoneal soft‐tissue sarcoma. Methods A retrospective analysis was conducted using the National Oncology Database, a proprietary database of aggregated tumor registries owned by IMPAC® Medical Systems (Sunnyvale, CA). Patients who received definitive surgery with negative or microscopic‐positive margins were included. Multivariate analysis was performed using the Cox proportional hazards model. Survival curves were estimated by the Kaplan–Meier method and were compared for statistical significance (P