Predictive factors for radiation-induced pituitary damage in pediatric patients with brain tumors

Abstract

Background and purpose: Multiple studies demonstrated hypothalamic-pituitary dysfunction in survivors of pediatric brain tumors. However, few studies investigated the trajectories of pituitary height in these patients and their associations with pituitary function. We aimed to evaluate longitudinal changes of pituitary height in children and adolescents with brain tumors, and their association with endocrine deficiencies.

Materials and methods: We conducted a retrospective analysis of 193 pediatric patients (54.9% male) diagnosed with brain tumors from 2002 to 2018, with a minimum of two years of radiological follow-up. Pituitary height was measured using MRI scans at diagnosis and at 2, 5, and 10 years post-diagnosis, with clinical data sourced from patient charts.

Results: Average age at diagnosis was 7.6 ± 4.5 years, with a follow-up of 6.1 ± 3.4 years. 52.8% underwent radiotherapy and 37.8% experienced pituitary hormone deficiency. Radiation treatment was a significant predictor of decreased pituitary height at all observed time points (p = 0.016, p < 0.001, p = 0.008, respectively). Additionally, chemotherapy (p = 0.004) or radiotherapy (p = 0.022) history and pituitary height at 10 years (p = 0.047) were predictors of endocrine deficiencies. ANOVA revealed an expected increase in pituitary height over time in pediatric patients, but this growth was significantly impacted by radiation treatment and gender (p for interaction = 0.005 and 0.025, respectively).

Conclusion: Cranial irradiation in pediatric patients is associated with impairment of the physiologic increase in pituitary size; in turn, decreased pituitary height is associated with endocrine dysfunction. We suggest that pituitary gland should be evaluated on surveillance imaging of pediatric brain tumor survivors, and if small for age, clinical endocrine evaluation should be pursued.

Keywords: Brain Tumors; Endocrine Deficiencies; Hypophysis; Hypothalamic-Pituitary Dysfunction; Irradiation; Late radiation effects; MRI.