Grossly-resected synovial sarcoma treated by the German and Italian Pediatric Soft Tissue Sarcoma Cooperative Groups: Discussion on the role of adjuvant therapies

Abstract Differently from adult oncologists that considered synovial sarcoma (SS) a tumor with uncertain chemosensitiveness, since two decades pediatric oncologists in Europe assumed that chemotherapy played an important role in SS treatment, so most pediatric patients were included in rhabdomyosarcoma protocols, receiving adjuvant chemotherapy regardless of risk factors. The German and Italian groups reviewed the data of grossly resected SS patients in order to define a risk-adapted treatment program for the next European protocol. A total of 150 patients < 21 years with localized SS who underwent initial gross resection between 1975 and 2002 were the object of this study. All but four cases received adjuvant chemotherapy. Post-operative radiotherapy was administered to 50% Group I and to 92% Group II patients. Five-year event-free survival (EFS) and overall survival (OS) were 77% and 89%, respectively. Survival rates were influenced by tumor size (EFS 92% and 56%, for size <= and >5 cm, respectively) and local invasiveness, not by surgical margins. No metastatic relapses occurred in Group I <= 5 cm patients, while the outcome was poor for T2B patients (EFS 41%) due to a high rate of metastatic relapse. Our study was unable to assess the role of adjuvant treatments in grossly-resected SS, but identified a subset of low-risk patients (IRS Group I, size <= 5 cm), for which the omission of adjuvant chemotherapy could be suggested, and a subset of high-risk patients (T2B), who need treatment intensification.