High-dose Busulfan and Melphalan As Conditioning Regimen for Autologous Peripheral Blood Progenitor Cell Transplantation in High-risk Ewing Sarcoma Patients: a Long-term Follow-up Single-center Study

The aim of this retrospective study was to analyze the outcome and identify risk factors associated to progression-free survival (PFS) in 47 children with high-risk Ewing sarcoma who underwent autologous peripheral blood stem cell (PBSC) transplantation in the authors' institution between 1995 and 2009. The conditioning regimen used in all patients consisted of high dose of busulfan and melphalan. Median age was 13 years (range: 4-21 years). Forty-three percent of patients had metastases at diagnosis. The probability of transplant-related mortality (TRM) was 6% +/- 3%. Recurrence/progressive disease was observed in 17 patients. The probability of recurrence/progression was 39% +/- 7%. With a median follow-up of 92 months (range: 6-168 months), the PFS was 56% +/- 4% for the whole group. In multivariate analysis, localized disease at diagnosis and obtaining complete remission (CR) by 3 months after transplantation were variables associated to better outcomes. The probability of PFS was 78% +/- 8% and 27% +/- 10% for patients with localized and metastatic disease at diagnosis, respectively (P = .0001). This retrospective study shows a high long-term survival using high dose of busulfan and melphalan as conditioning regimen in children with high-risk Ewing tumors. Patients with localized disease at diagnosis and those with good response to treatment before or after transplant would benefit most.