[Results of treatment of rhabdomyosarcomas (RMS) in children. A report of the Cooperative Soft Tissue Sarcoma Study (CWS-81) of the Society of Pediatric Oncology].

This analysis refers to 129 children with RMS who were treated between 1981 and 1985 according to the protocol guidelines of the CWS-81 study. The duration of chemotherapy depended on the initial post-operative stage. Patients with stage I and IIA were not to receive any radiotherapy, and patients with primary stage III were treated according to the results of a 16-week chemotherapy treatment: either without radiation (stage Ipc), or with radiotherapy using 40 Gy (stage (IIpc) or 50 Gy (stage IIIpc). The median time of observation was 27 months (Juni 1985). The essential results of the study are as follow: RMS of the extremities in stages I and IIA need radiotherapy, contrary to all other localisations with the same stages. Patients with RMS stage III who are tumor-free after initial chemotherapy (histologically checked) do not need radiotherapy. Patients with microscopic residue (IIpc) or macroscopic residue (IIIpc) after pretreatment showed no difference in their local relapse rate, whereas metastases were found only in the group having macroscopic tumor residue up to week 16. An additional examination of this study observed tumor response during initial chemotherapy and its relationship to prognosis. This analysis showed that the degree of tumor regression per unit of time permits the most favorable prognostic statement. Patients with clinical complete remission after 7/9 weeks showed a 100% relapse-free chance of survival, independent of localisation, tumor size or histological subtype. Those with a tumor reduction of greater than 2/3 but no complete remission showed 67% chance of survival, and those with greater than 1/3-2/3 tumor reduction had 25%. Tumor response kinetics under initial chemotherapy allows better individual therapy in the future. The overall result of the study concerning localisation and stage corresponds to that of the IRS I and II studies. Patients with undifferentiated sarcomas, extraossary Ewing's sarcoma and synovial sarcomas can be treated according to the same principles as RMS, since no significant differences in prognosis could be found.