Post-relapse survival in patients with Ewing sarcoma

Background: Post-relapse survival (PRS) was evaluated in patients with Ewing sarcoma (EWS) enrolled in chemotherapy protocols based on the use of high-dose chemotherapy with busulfan and melfalan (HDT) as a first-line consolidation treatment in high-risk patients. Procedure: EWS patients enrolled in ISG/SSG III and IV trials who relapsed after complete remission were included in the analysis. At recurrence, chemotherapy based on high-dose ifosfamide was foreseen, and patients who responded but had not received HDT underwent consolidation therapy with HDT. Results: Data from 107 EWS patients were included in the analysis. Median time to recurrence (RFI) was 18 months, and 45 (42%) patients had multiple sites of recurrence. Patients who had previously been treated with HDT had a significantly (P=0.02) shorter RFI and were less likely to achieve a second complete remission (CR2). CR2 status was achieved by 42 (39%) patients. Fifty patients received high-dose IFO (20 went to consolidation HDT). The 5-year PRS was 19% (95% CI 11 to 27%). With CR2, the 5-year PRS was 48% (95% CI 31 to 64%). Without CR2, median time to death was six months (range 1-45 months). According to the multivariate analysis, patients younger than 15 years, recurrence to the lung only, and RFI longer than 24 months significantly influenced the probability of PRS. Conclusions: Age, pattern of recurrence, RFI, and response to second-line chemotherapy influence post-relapse survival in patients with recurrent Ewing sarcoma. No survival advantage was observed from chemotherapy consolidation with HDT. Pediatr Blood Cancer 2015;62:994-999.