A Multicenter Retrospective Outcomes Analysis of Patients with Localized Synovial Sarcoma

To identify clinicopathologic factors associated with outcomes in patients with localized synovial sarcoma (SS). We retrospectively reviewed 248 patients with localized SS treated across three US quaternary medical centers between 2000 and 2024. Demographics, tumor characteristics, and treatments, including perioperative chemotherapy and radiotherapy (RT), were assessed. Disease-free survival (DFS) and overall survival (OS) were estimated via Kaplan-Meier analysis, and Cox regression was used for univariable and multivariable analysis, including significant univariate factors and confounders such as age and tumor size. Median follow-up was 5.2 years; median age at diagnosis was 35 years (IQR, 26-46). Median DFS was 110.3 months. Perioperative chemotherapy was given to 150 (60%) patients, whereas perioperative RT was given to 173 (69.8%) patients. Multivariable analysis showed that tumor size correlated with worse DFS (P < 0.001) and OS (P < 0.001), whereas a location in the chest wall, trunk, or extremities correlated with improved DFS (P = 0.006). Percent tumor necrosis was associated with worse OS (P = 0.04), whereas R0 (P = 0.002) resection margins correlated with improved OS. Perioperative RT or chemotherapy did not correlate with OS or DFS in the whole cohort, though patients with tumor size ≥10 cm (n = 47) showed worse OS when receiving perioperative chemotherapy only as opposed to combined perioperative chemotherapy and RT (P = 0.006). Tumor size, location, margin status, and tumor necrosis are independent prognostic factors in localized SS. Combined perioperative chemotherapy and RT correlated with improved OS in patients with tumors larger than 10 cm.

SS is a rare, aggressive malignancy with limited perioperative data. In this multi-institutional study of 248 patients with localized disease, tumor size, location, and margin status predicted recurrence and survival. Combined perioperative chemotherapy and RT benefited patients with larger tumors but not across the overall cohort, supporting risk-adapted management.