[Allogeneic hematopoietic stem cell transplantation in children's acute myeloblastic leukemia: Survival and relapse]

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is indicated for children with high-risk (HR) acute myeloid leukemia (AML).

To evaluate overall survival (OS), event-free survival (EFS), relapse, and non-relapse mortality (NRM).

This was a retrospective descriptive study including children (<18 years) with AML who underwent allo-HSCT from an HLA-identical sibling donor between 1999 and 2023. Conditioning regimens consisted of busulfan-cyclophosphamide (BuCy) or total body irradiation-cyclophosphamide (TBI-Cy). Stem cell sources were bone marrow (BM) or peripheral blood stem cells.

Fifty-two children were included, with a median age of 13 years (range: 3-17). Patients were classified as HR in 60.3% of cases. The median time from diagnosis to transplantation was 5 months (range: 3-40). At transplantation, 75% of patients were in first complete remission (CR1). The stem cell source was BM in 84.6% of cases, and BuCy was used in 90.4% of patients. The graft rejection rate was 5.8%. The cumulative incidences of acute and chronic graft-versus-host disease (GVHD) were 20% and 23.4%, respectively. The cumulative incidence of NRM was 7.7%, while relapse occurred in 44.7% of patients. After a median follow-up of 30 months (range: 39 days-18 years), the 3-year OS and EFS were 51.6% and 47.8%, respectively.

Post-allo-HSCT relapse remains a major challenge in pediatric AML. Intensification of pre-transplant conditioning, busulfan pharmacokinetic monitoring, and the development of targeted therapies may help reduce the risk of relapse.