Perioperative radiotherapy is associated with improved survival among patients with synovial sarcoma: A SEER analysis

Background and Methods: We examined the outcomes of synovial sarcoma (SS) patients in a national database. We identified 1,189 patients from the Surveillance, Epidemiology, and End Results (SEER) database with data on site and extent of surgery. We excluded patients diagnosed before 1990, <18 years, or lacking pathologic confirmation. Using Kaplan-Meier and Cox proportional hazards analyses, we determined predictors of overall (OS) and disease-specific survival (DSS). Results: The mean age was 41, 49.3% were female, and 82.2% were white. Radiotherapy (RT) was administered to 57.5%. On multivariable analysis, age at diagnosis, sex, race, anatomic site, SEER summary stage, tumor size, surgery type, and RT predicted OS. Similar predictors of DSS were identified. The hazard ratio (HR) for OS was 0.65 (95% CI 0.48-0.88) in favor of RT and 0.62 (95% CI 0.45-0.86) for DSS. Five-year OS improved 8.4 ± 1.0% with RT (P = 0.003), and five-year DSS improved 7.7 ± 1.0% with RT (P = 0.015). Conclusions: In the largest study to date examining the role of RT in synovial sarcoma, we observed that RT was associated with a statistically significant improvement in oncologic outcome among SS patients. These data support the use of RT in the multi-modality treatment of patients with SS.