Increased susceptibility to long-term complications in leukemia survivors who received hematopoietic stem cell transplantation during adolescence

Hematopoietic stem cell transplantation (HSCT) is essential for curing high-risk or relapsed acute leukemia but entails lifelong morbidities. Adolescents and young adults may be particularly vulnerable; however, data on the global risk of long-term complications in survivors who underwent HSCT during adolescence are lacking. Using the French Leucémie Enfant Adolescent (LEA) cohort, we compared late complications and quality of life (QoL) in survivors transplanted at ≥15 years versus <15 years. We included 168 adolescents (≥15 years of age at HSCT) and 446 children (<15 years of age at HSCT) matched at best 1:3 on sex, type of leukemia, total body irradiation use, history of relapse, and follow-up duration. Cumulative morbidity was modelled with a five-state multistate model (0 to ≥4 complications). After a mean follow-up of 8.8 years for adolescents and 9.5 years for children, adolescents had a mean of 2.1±0.1 complications compared with 1.6±0.1 in younger survivors (p <0.001). Higher incidences were noted for cardiomyopathy, chronic kidney disease, secondary neoplasms, iron overload and osteonecrosis. The multi-state model revealed earlier onset and faster accumulation of complications in adolescents. QoL scores did not differ between groups. HSCT during adolescence is associated with earlier and heavier long-term morbidity, underscoring the need for age-tailored survivorship care and integration of AYA-specific risks into follow-up guidelines.