The Benefit of Adjuvant Radiotherapy in High-grade Nonmetastatic Retroperitoneal Soft Tissue Sarcoma

Abstract

OBJECTIVES: Controversy persists on the use of adjuvant radiotherapy (RT) in patients with retroperitoneal sarcoma (RPS). High-grade disease is known to be associated with decreased local control and overall survival (OS). Because RT has proven beneficial for local control and OS in patients with high-grade extremity soft tissue sarcoma, we evaluated the efficacy of adjuvant RT in high-grade RPS. METHODS: The Surveillance, Epidemiology, and End Results database was used to identify patients with pathology-confirmed RPS from 1973 to 2010. Clinical characteristics and outcomes were analyzed. RESULTS: Of 480 total patients, 144 (30.0%) received postoperative radiation. Patients who received adjuvant RT had improved median OS (36 mo) compared with those who did not (27 mo, hazard ratio [HR]=0.79, P=0.023). On multivariate analysis the use of adjuvant RT (HR=0.80; 95% confidence interval [CI], 0.65-0.98; P=0.029), male sex (HR=1.32; 95% CI, 1.10-1.59; P=0.003), age above 65 years (HR=1.38; 95% CI, 1.15-1.67; P=0.001), and increasing the Surveillance, Epidemiology, and End Results historical stage (HR=1.46; 95% CI, 1.21-1.76; P<0.001) were all prognostic factors for OS. CONCLUSIONS: In a large retrospective analysis, postoperative RT improved OS in high-grade RPS patients. As such, adjuvant RT should be strongly considered in all patients with high-grade RPS. The optimal timing of RT relative to surgery requires further study.