Outcomes of hematopoietic stem cell transplantation in pediatric acute lymphoblastic leukemia: a multicenter Brazilian cohort study.

Acute leukemias are prevalent among children and adolescents, with survival rates exceeding 90%, but high-risk cases often require hematopoietic stem cell transplantation (HSCT). Limited data are available on HSCT outcomes for pediatric acute lymphoblastic leukemia (ALL) in low- and middle-income countries. This Brazilian multicenter retrospective cohort study analyzed outcomes of ALL patients aged up to 18 years who underwent HSCT from January 2010 to June 2020. A total of 439 patients were included (69% male, 78.9% B-ALL). Unrelated donor transplants accounted for 49.9%, and haploidentical transplants for 18.9%. Bone marrow (82.6%) was the predominant stem cell source. Transplants occurred in the first or second complete remission (CR) in 38.7% and 44.2% of cases, respectively. The 100-day cumulative incidence of acute GvHD was 46.1%, and chronic GvHD after 100 days occurred in 25.5%. At five years, overall survival and event-free survival were 52.4% and 51.7%. By day +100, sepsis was the leading cause of mortality (42.3%), whereas relapse accounted for 76.3% of deaths thereafter. Findings align with HSCT literature, demonstrating similar outcomes despite challenges in developing countries and providing a basis for further research.