BackgroundThe prognosis in patients with relapsed Ewing sarcoma is unfavorable. Our investigation identifies factors predicting for the outcome following relapse.ProcedureWe analyzed type of relapse, time to relapse and overall survival after relapse (OSr) in 714 patients with first recurrence. All patients had been treated within the Cooperative Ewing Sarcoma Studies (CESS) 81 or 86, or the European Intergroup CESS (EICESS 92). OSr time was calculated from diagnosis of first relapse to last follow‐up or death.ResultsMedian follow‐up time from diagnosis of primary disease was 2.2 years (mean = 4.0; range: 0.2–24.9). Relapse sites were local in 15%, combined local and systemic in 12%, and systemic in 73%. Among patients with a localized primary tumor, 20% relapsed locally, while 12% showed combined and 68% systemic relapse. When the primary disease was disseminated, 82% developed systemic, 13% combined, and 5% local relapse. Five‐year OSr was 0.13 (SE = 0.01). Outcome following local relapse, with a 5‐year survival rate of 0.24 (P < 0.001), was superior to outcome after systemic or combined recurrence. Five‐year OSr was 0.07 (SE = 0.01) in patients who relapsed 0–2 years after the diagnosis of primary disease, as compared to a 5‐year OSr of 0.29 (SE = 0.03) when relapse occurred later.Conclusions5‐year OSr in Ewing sarcoma is poor (<0.2). Prognostically favorable factors are: late onset (>2 years) and strictly localized relapse. Pediatr Blood Cancer 2011; 57: 549–553. © 2011 Wiley‐Liss, Inc.

Cyclophosphamide may be able to replace ifosfamide in consolidation treatment of standard-risk Ewing sarcoma. However, some uncertainty surrounding the noninferiority of VAC compared with VAI remains at this stage. The ongoing comparative evaluation of long-term renal and gonadal toxicity is crucial to decisions regarding future patients.