Synovial sarcoma prognostic factors and patterns of failure

From 1970 to 1999, 44 patients with synovial sarcoma were seen at the University of Iowa. Tumor size was greater than or equal to5 cm in 24 (55%). Histologic classification was biphasic in 26 (59%) and monophasic in 18 (41%). Seven patients (16%) had distant metastasis at initial presentation. For the 37 nonmetastatic patients, local treatment consisted of wide local excision in 29 and amputation in 8; chemotherapy was administered to 10. For the 29 who underwent wide local excision, microscopic resection margins were negative in 18 and positive in 11; 19 received postoperative radiotherapy. The 5-, 10-, and 20-year overall survival rates for the nonmetastatic group were 65.6%, 45.5%, and 37.8%. On multivariate analysis using age as a continuous covariate, younger age (p = 0.028), biphasic histology (p = 0.014), and extremity sites treated with limb-sparing surgery (p = 0.001) were found to be predictors of a better overall survival. No local failures were found after 5 years from initial diagnosis. On multivariate analysis, tumor location at an extremity site was the only variable marginally found to have a better local control (p = 0.065). Of the 19 patients who developed distant metastasis, 5 (26%) failed >5 years and 2 (11%) failed >15 years of follow-up. Younger age, biphasic histology, and extremity sites were found to have a better survival outcome. Late distant relapses can occur with synovial sarcoma.