We thank Drs Gilman and Oesterheld for their comments on our paper.1 The aim of our study was to identify risk factors associated with progression-free survival in patients with Ewing's sarcoma undergoing autologous stem cell transplantation (ASCT). We identified three risks factors: metastatic disease at diagnosis, recurrence prior to transplantation and patients with poor performance score were associated with higher rates of treatment failure and consequently lower progression-free survival rates. We acknowledge data analyzed are subject to the limitations of using an observational database and described in our manuscript. Contrary to the suggestion, the sites of metastases are provided in our paper; lung metastasis was the most frequent. Site of metastases was not associated with progression-free survival in our analysis. We did not intend this paper to serve as a formal comparison of progression-free survival rates after conventional therapy for Ewing sarcoma and this is stated in our paper. We agree that the role of ASCT can only be addressed satisfactorily when patients with similar disease characteristics are randomized to receive one of the two treatment options. The data presented in our report are sobering, considering that patients enrolled on clinical trials are subject to an intent-to-treat analysis, whereas our cohort of patients was analyzed from the time of ASCT. It is our intent this report will serve as a reminder to clinicians to enroll their patients on prospective clinical trials such as the Euro EWING 99 so that optimal treatment recommendations are available at the completion of that study.