[Analysis of prognostic factors in rhabdomyosarcoma. Preliminary univariate and multivariate results of the Cooperative Soft Tissue Sarcoma Study (CWS-81)].

The characteristics of 129 children with rhabdomyosarcoma entered into the CWS-81 study between 1981 and 1984 were examined for their relationship to prognosis. Prognosis was defined as relapse-free survival time. The trial was stratified to clinical groups depending on the surgical procedure at onset. So, each group had to be analysed separately. The patient characteristics of group I/IIA mostly related to prognosis were primary site (disease in extremities, unfavorable; paratesticular primary, favorable) and tumor infiltration into adjacent bone (bone infiltration, unfavorable). In group IIB/III the degree of tumor response within 7-9 weeks, chemotherapy exclusively given, was the only characteristic significantly related to prognosis (greater than 2/3 tumor reduction, favorable; less than 2/3 tumor reduction, unfavorable). Other prognostic factors as histological subtype, primary site, tumor diameter, lymph node involvement, bone infiltration, sex and age had no significant influence. The tumor diameter was the only characteristic with significant influence in group IV. The larger the tumor diameter, the poorer was prognosis. Furthermore, the alveolar subtype was seen predominantly in non-responding tumors of group IV. In group III, we fitted the patient characteristics in a multivariate regression model (Cox's model). The degree of tumor response within 7-9 weeks was analysed to be the main hazard function related to prognosis. In future, the degree of tumor response within a certain time can be used as the measurement of effectiveness of chemotherapy. So, in patients of group III and IV a risk adapted therapeutic procedure can be undertaken.