Prognostic factors for survival in children who relapsed after allogeneic hematopoietic stem cell transplantation for acute leukemia

Background Post‐transplant relapse has a dismal prognosis in children with acute leukemia undergoing allogeneic hematopoietic stem cell transplantation (allo‐HSCT). Data on risk factors, treatment options, and outcomes are limited. Procedure In this retrospective multicenter study in which a questionnaire was sent to all pediatric transplant centers reporting relapse after allo‐HSCT for a cohort of 938 children with acute leukemia, we analyzed 255 children with relapse of acute leukemia after their first allo‐HSCT. Results The median interval from transplantation to relapse was 180 days, and the median follow‐up from relapse to the last follow‐up was 1844 days. The 3‐year overall survival (OS) rate was 12.0%. The main cause of death was disease progression or subsequent relapse (82.6%). The majority of children received salvage treatment with curative intent without a second HSCT (67.8%), 22.0% of children underwent a second allo‐HSCT, and 10.2% received palliative therapy. Isolated extramedullary relapse (hazard ratio (HR): 0.607, P = .011) and relapse earlier than 365 days post‐transplantation (HR: 2.101, P