The Euro-E.W.I.N.G. 99 trial aimed to improve the dismal prognosis of patients with primary disseminated multifocal Ewing tumors (PDM-ET) with a dose-intense treatment concept.

From 1999 to 2005, 281 patients with PDM-ET were enrolled onto the EURO-E.W.I.N.G. 99 trial. Median age was 16.2 years (0.4–49). Recommended treatment consisted of 6 VIDE, one VAI cycle, local treatment (surgery and/or radiotherapy), and high-dose busulfan-melphalan followed by autologuous 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%. Six VIDE cycles were completed by 250 patients (89%); 169 (60%) received HDT/SCT. Forty-six children less than 14 years and HDT/SCT achieved a 3-year EFS of 45%. Cox regression analyses demonstrated increased risk at diagnosis for patients over 14 years (HR 1.6), a primary tumor volume > 200ml (HR 1.8), more than one bone metastatic site (hazard ratio: 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 ≤3 (82 patients), 25% for score > 3 to < 5 (102 patients), and 10% for score ≥5 (70 patients), p< 0.0001.

PDM-ET patients may survive with intensive multimodal therapy. Age, tumor volume, and extent of meta-static spread are relevant risk factors. A score based on these factors identifies PDM-ET patients may facilitate risk adapted treatment approaches.