Primary disseminated multifocal Ewing sarcoma: results of the Euro-EWING 99 trial.

To improve the poor prognosis of patients with primary disseminated multifocal Ewing sarcomas (PDMES) with a dose-intense treatment concept. From 1999 to 2005, 281 patients with PDMES were enrolled onto the Euro-EWING 99 R3 study. Median age was 16.2 years (range, 0.4 to 49 years). Recommended treatment consisted of six cycles of vincristine, ifosfamide, doxorubicin, and etoposide (VIDE), one cycle of vincristine, dactinomycin, and ifosfamide (VAI), local treatment (surgery and/or radiotherapy), and high-dose busulfan-melphalan followed by autologous stem-cell transplantation (HDT/SCT). After a median follow-up of 3.8 years, event-free survival (EFS) and overall survival (OS) at 3 years for all 281 patients were 27% +/- 3% and 34% +/- 4% respectively. Six VIDE cycles were completed by 250 patients (89%); 169 patients (60%) received HDT/SCT. The estimated 3-year EFS from the start of HDT/SCT was 45% for 46 children younger than 14 years. Cox regression analyses demonstrated increased risk at diagnosis for patients older than 14 years (hazard ratio [HR] = 1.6), a primary tumor volume more than 200 mL (HR = 1.8), more than one bone metastatic site (HR = 2.0), bone marrow metastases (HR = 1.6), and additional lung metastases (HR = 1.5). An up-front risk score based on these HR factors identified three groups with EFS rates of 50% for score or= 5 (70 patients; P < .0001). PDMES patients may survive with intensive multimodal therapy. Age, tumor volume, and extent of metastatic spread are relevant risk factors. A score based on these factors may facilitate risk-adapted treatment approaches.