The response to initial chemotherapy as a prognostic factor in localized Ewing's sarcoma.

Ninety-five children with localized Ewing's sarcoma were included in a prospective cooperative study. All patients received initial chemotherapy with the purpose of early prevention of metastases and improvement of the conditions of the subsequent local therapy, radiotherapy in all cases, surgical resection in selected cases. Clinical response to initial chemotherapy was evaluated in 67 patients who had measurable soft tissue mass or functional symptoms. This response appeared highly correlated with outcome as the disease-free survival was 57.3% for the 41 good responders and 9% for the 26 bad responders (P less than 0.00001), though 23 of these bad responders reached complete remission with radiotherapy. This study also confirms the prognostic significance for survival of the site of the primary tumor on axial skeleton or on limbs. Nevertheless, this factor had no predictive value for response to chemotherapy, which thus appears to be an independent factor.