Prepubertal Initiation of Imatinib is Associated with Reduced Final Height in Children with Chronic Myeloid Leukemia.

Imatinib in children with chronic myeloid leukemia (CML) is associated with growth deceleration. However, the long-term impact on final height remains less clear. The aim was to evaluate the effect of prolonged imatinib on linear growth at skeletal maturity. A cross-sectional study was conducted at a single center (2020-2021). Patients with chronic-phase CML on imatinib, diagnosed before 13 years and who had attained skeletal maturity at enrollment, were included. Anthropometry, sexual maturity rating, bone age, and evaluation for causes of short stature were performed. Longitudinal height data were retrieved from clinic records and compared with population-specific growth charts. Of 46 screened patients, 13 fulfilled the inclusion criteria. Mean age at diagnosis and enrollment was 9.3 ± 2.3 and 23.7 ± 2.6 years. The median duration of imatinib therapy was 14.3 years (IQR: 14.2-16), with 184.4 patient-years of follow-up. Mean height z-score declined from -0.6 ± 1.2 at diagnosis to -1.1 ± 0.9 at maturity (p = 0.04). In those administered imatinib before the onset of pubertal growth spurt, the decline was significant (-0.5 ± 0.6 to -1.3 ± 0.6, p = 0.03), compared to those administered after the pubertal growth spurt (p = 0.60). In one of the longest follow-up cohorts of children with CML reported to date, imatinib resulted in growth deceleration, particularly when initiated before the onset of pubertal growth spurt. Despite catch-up growth during adolescence, final height z-scores remained reduced at skeletal maturity.