Localized synovial sarcoma: A single institutional study of 191 patients with a minimum follow-up of 5 years for survivors.

PURPOSE: Factors affecting long-term outcomes of synovial sarcoma (SS) remain unknown. Here, we aimed to investigate the long-term oncological outcomes and prognostic factors in a large group of patients with surgically-treated localized SS. PATIENTS AND METHODS: Between 1980 and 2011, 191 patients (94 males and 97 females) were treated at a single hospital with a minimum follow-up of 5 years for survivors. The median age was 35 years (range, 3-80 years), and the median follow-up period was 83 months (range, 3-235 months). RESULTS: Disease-specific survival was 76.4% and 60.4% at 5 and 10 years, respectively. Local recurrence occurred in 23 patients at a median of 33 months (range, 6-158 months), and metastasis occurred in 73 patients at a median of 20 months (range, 2-166 months). In multivariate analysis, grade 3 tumors sized ≥5 cm were significantly associated with worse survival. Ten patients (5.2%) developed metastasis more than 5 years after surgery. CONCLUSION: Tumor size and grade govern prognosis in surgically-treated localized SS in long-term settings. If adequately treated patients have not developed metastases for 5 years after surgery, the risk of subsequently developing metastases was lower than previously reported.