Synovial sarcoma - Identification of low and high risk groups

BACKGROUND. Synovial sarcoma, one of the most common soft tissue sarcomas t hat occur in adolescents and young adults, is generally viewed and treated as a high grade sarcoma. However, the authors' own experience and some prev ious studies have indicated that it has a wide spectrum of biologic behavio r and that low and high risk subgroups of patients with synovial sarcoma ca n be identified. METHODS, A total of 121 consecutive patients with synovial sarcoma (includi ng 66 males and 55 females ages 9-74 years), treated primarily or secondari ly at 2 large referral centers for musculoskeletal tumors, were included in a statistical analysis conducted to identify independent prognostic factor s. RESULTS. There were local recurrences in 38 patients (31%), usually after i nadequate primary surgery outside the referral centers; 64 patients (54%) d eveloped metastasis, primarily to the lungs. The estimated 5-, 10-, and 15- year survival rates were 60%, 50%, and 45%, respectively (the mean follow-u p for surviving patients was 9.8 years, with a range of 1-30 years). In mul tivariate analysis, independent risk factors for local recurrence included larger tumor size and primary surgical resection outside the referral cente r. Independent risk factors for metastasis were older patient age, tumor wi th poor histologic differentiation, and tumor necrosis. For tumor-related d eath, the independent risk factors were older patient age, tumor with poor histologic differentiation, and larger tumor size. Local recurrence was ass ociated with a 3.66-fold increased risk of tumor-related death. A low risk group (patient age <25 years, tumor size <5 cm, and no histologic evidence of poorly differentiated tumor) with 88% overall disease free survival was identified, as was a high risk group (patient age greater than or equal to 25 years, tumor size greater than or equal to 5 cm, and poorly differentiat ed tumor) with 18% overall disease free survival (P < 0.001). CONCLUSIONS. The identification of low and high risk synovial sarcoma patie nts indicates that synovial sarcomas are not uniformly high grade tumors. I t also indicates that treatment strategies should be modified for these ris k groups. Adequate primary surgery is essential to both local control and o utcome for synovial sarcoma patients. [See editorial on pages 2497-8, this issue.] (C) 1999 American Cancer Society.