The value of high-dose chemotherapy in patients with first relapsed Ewing sarcoma.

BACKGROUND: Prognosis of patients with relapsed Ewing sarcoma (ES) is poor. The 5-year overall survival (OS) is 13%. We analyzed high-dose chemotherapy (HDtx) versus conventional chemotherapy (CHtx) in patients with relapsed ES. PROCEDURE: Data from 239 patients with first relapse, registered during 2000-2011 in the ES relapse registry of the Cooperative Ewing Sarcoma Study Group (CESS) were analyzed. RESULTS: Of 239 patients, 200 received various non-HDtx second-line CHtx regimens. Seventy-three patients had additional HDtx followed by autologous stem cell rescue. The 2-year event-free survival (EFS) was 10% (SE = 0.02) in patients treated without HDtx and 45% (SE = 0.09) in patients treated with HDtx. In a second step, we focused on those patients who achieved complete remission (CR) or partial remission (PR) after four to six cycles of conventional second-line CHtx. Here, the 2-year EFS was 31% (SE = 0.08) without additional HDtx and 44% (SE = 0.09) with additional HDtx. In addition, multivariate regression analysis indicates absence of HDtx treatment, with a Hazard ratio (HR) of 2.90 (95% CI 1.41-6.0), and early relapse, with a HR of 4.76 (95% CI 2.31-9.78), as independent prognostic factors for EFS. CONCLUSION: Additional HDtx may contribute to further reduce the risk of further events in patients who respond to conventional second-line CHtx.