Metastatic rhabdomyosarcoma and histologically similar tumors in childhood: a retrospective European multi-center analysis.

This is a retrospective analysis of children with metastatic soft tissue sarcoma (STS) registered in the major European STS studies: the SIOP MMT 75, the German CWS 1981 and 1986 studies, the Italian STS study, and the United Kingdom Children's Cancer Study Group centres in Britain. One hundred forty-six patients out of 164 were evaluable in this analysis. The median age was 7 years (1-18) and the male/female ratio was 1.3:1. The median follow-up was 80 months (7-171). The most common site of the primary tumor was the extremity (28%), which correlated well with the high preponderance (39%) of the alveolar type of RMS (aRMS). There was no dominant combination of metastatic sites and the most common single organ with metastasis was the lung (41%). Since the therapy depended on the country and period in which the patient was treated, we did not analyse the outcome and therapy together. Complete remission was achieved in 50% of the cases. Those with aRMS had a good chance of achieving CR (61%) but the majority of these patients relapsed (78%). The median time needed to relapse was 243 days (53 days to 47 months) for all patients. Analysis of the site of the primary tumor showed that the CR rate was best in the GU non-BP site (62%) and worst in PM cases (35%). The overall survival and DFS rate were 18% and 15%, respectively. The GU non-BP patients had a DFS rate of 50%, while the rate for all other sites varied between 12% and 18%. A total of 24 patients remained in CCR. The majority of them had embryonal type of RMS and metastases in only one anatomic site. Our analysis indicates that the best chance of prolonged survival was in metastatic GU non-BP cases, patients with embryonal type RMS, and those with metastases in only one organ. To try to improve the treatment of metastatic STS, a prospective European cooperative study was started in 1989.