Long-Term Follow-up of High-Dose Chemotherapy with Autologous Stem Cell Transplantation in Children and Young Adults with Metastatic or Relapsed Ewing Sarcoma: A Single-Institution Experience

Forty-seven patients with metastatic disease at diagnosis or recurrent Ewing sarcoma (EWS) received high-dose chemotherapy (HDC) followed by tandem (n = 20, from February 13, 1997, to October 24, 2002) or single (n = 27, from October 1, 2004, to September 5, 2018) autologous hematopoietic stem cell transplantation (ASCT). To our knowledge, this is the largest single-institution study with sustained long-term follow-up exceeding 10 years. All patients who underwent single ASCT received a novel conditioning regimen with busulfan, melphalan, and topotecan. The overall survival (OS) and disease-free survival (DFS) were 46% and 37% at 10 years and 42% and 37% at 15 years, respectively. Disease status at transplant and the time to disease relapse prior to ASCT were identified as important prognostic factors in OS, DFS, and risk of relapse. At 10 years, patients who underwent transplantation in first complete response (1CR) had an excellent outcome (OS 78%), patients in 1CR/second complete response (2CR)/first partial response (1PR) had an OS of 66%, and patients at third or more complete response, second or more partial response, or advanced disease had an OS of 26%. Ten-year OS for patients without a history of relapse, with late relapse (≥2 years from diagnosis), or with early relapse (<2 years from diagnosis) was 75%, 50%, and 18%, respectively. Selected patients in 1CR, 2CR, 1PR, and with late relapse had excellent, sustained 10- and 15-year OS and DFS.