Synovial sarcoma: Prognostic significance of tumor size, margin of resection, and mitotic activity for survival

Purpose: The present study serves to describe outcomes-based prognostic variables characteristic of synovial cell sarcoma. Patients and Methods: An analysis was performed of a prospectively compiled data base of 48 consecutive patients with extremity and truncal synovial sarcomas seen between 1966 and 1994. Results: No local recurrences were observed among 27 patients who presented with localized primary disease. Patients with synovial sarcomas less than 5 cm in size had a cancer-specific survival rate at 10 years of 100%, compared with a 10-year survival rate of 32% and 0% for those with sarcomas 5 to 10 cm and greater than 10 cm, respectively (P =.002). Patients with synovial sarcomas with less than 10 mitoses per 10 high-power fields (hpf) had a 10-year cancer-specific survival rate of 46%, compared with a 10-year survival rate of 14% for those with sarcomas with greater than 10 mitoses per 10 hpf (P =.04). Patients with a clean margin excision of sarcoma were found to have a 10-year caneer-specific survival rate of 43%, compared with 0% for those with microscopic positive margins (P =.03), Among 14 patients treated with neoadjuvant chemotherapy, seven (50%) had objective responses. Conclusion: Local control for patients with nonmetastatic disease was excellent. The overall cancer-specific survival rate for patients with localized synovial sarcoma was 34% at 10 years. Primary tumor size, margin of resection, and mean mitotic activity were prognostic factors for survival in synovial sarcoma. There was a high objective response rate to treatment with neoadjuvant chemotherapy; however, there were no detectable beneficial effects on survival in the subset of patients treated with chemotherapy versus nonrandomized patients who received no chemotherapy. Patients with synovial sarcomas greater than or equal to 5 cm in size, microscopic positive margins, and/or mean mitotic activity greater than 10 mitoses per 10 hpf should be targeted for new therapeutic studies. (C) 1996 by American Society of Clinical Oncology.