Purpose: To identify prognostic factors related to outcome in 219 children and adolescents with synovial sarcoma.
Patients and methods: We combined the experiences of the four following research groups: Cooperative Weichteilsarkomastudie Group, Germany (n = 95); St. Jude Children's Research Hospital, Memphis, TN (n = 49); Istituto Nazionale dei Tumori, Milan, Italy (n = 33); and The University of Texas M.D. Anderson Cancer Center, Houston, TX (n = 42). Kaplan-Meier and Cox proportional hazard analyses were performed.
Results: The median age at diagnosis was 13 years (range, 1 to 20 years), and the median follow-up was 6.6 years (range, 0.5 to 30.7 years). The estimated 5-year overall survival and event-free survival rates for the entire group were 80% +/- 3% (SE) and 72% +/- 3%, respectively. A previously unreported interaction between tumor size and invasiveness was observed that statistically significantly related to outcome. In multivarible analysis, patients with T1B and T2B disease (hazard ratio [HR] = 5.6, 95% confidence interval (CI), 1.9 to 16.2; and HR = 5.9, 95% CI, 2.1 to 16.4, respectively) or Intergroup Rhabdomyosarcoma Study (IRS) Clinical Group III and IV disease (HR = 2.7, 95% CI, 1.2 to 6.5; and HR = 14.1, 95% CI, 4.3 to 31.3, respectively) had poor overall survival. Treatment with radiotherapy was related to improved overall survival (HR = 0.4; 95% CI, 0.2 to 0.7). In IRS Group III patients, objective response to chemotherapy (18 of 30, 60%) correlated with improved survival.
Conclusion: Clinical group, tumor size, and invasiveness are important prognostic factors. Multicenter randomized clinical trials are needed to determine both the effect of chemotherapy on survival and the necessity of local radiotherapy in patients with completely resected tumors.