Undernutrition and Pubertal Timing in Female Survivors of Medulloblastoma and Other Embryonal Tumors.

CONTEXT Children with brain tumors may have pubertal onset at an inappropriately young chronologic age. Hypothalamic-pituitary irradiation ≥18 Gy has been found to be a risk factor; age at irradiation is associated with pubertal timing. However, the underlying mechanisms are unknown. OBJECTIVE To determine the impact of body mass index (BMI) and catch-up growth on pubertal timing in females treated for medulloblastoma and other embryonal tumors. DESIGN, SETTING, AND PATIENTS Retrospective cohort analysis of 90 female patients treated for medulloblastoma and other embryonal tumors at Dana-Farber Cancer Institute/Boston Children's Hospital between 1996 and 2016. 18 individuals met inclusion criteria with a mean±SD follow-up of 11.9±3.4 years. MAIN OUTCOME MEASURES Multiple linear regression models for age at pubertal onset and bone age discrepancy from chronologic age at pubertal onset assessed the joint influences of age at irradiation, hypothalamic irradiation dose, undernutrition duration, BMI SDS at pubertal onset, and catch-up BMI SDS. RESULTS The mean±SD age of pubertal onset was 9.2±1.3 years and hypothalamic radiation dose was 31.9±9.9 Gy. There was a direct relationship between age at irradiation and age at pubertal onset (β=0.323±0.144 [standard error] year per year, p=0.04) that was significantly attenuated after adjusting for BMI SDS at pubertal onset (p=0.5) and catch-up BMI SDS (p=0.08), suggesting that BMI is a mediator. CONCLUSIONS Both absolute and catch-up BMI SDS at pubertal onset are significant mediators of pubertal timing and bone age discrepancy in pediatric medulloblastoma and other embryonal tumors, and thus, are targetable risk factors to optimize pubertal timing.