SUN-694 - Longitudinal Body Mass Index Change in Childhood Brain Tumor Survivors

Introduction:

Childhood brain tumor (CBT) survivors face substantial long-term metabolic and endocrine morbidity related to tumor location and treatment exposures. Among the most prevalent and clinically consequential outcomes is excessive weight gain, which can contribute to cardiometabolic disease and reduced quality of life. We aimed to identify the clinical, treatment-related, and endocrine factors associated with BMI changes in this high-risk population.

Methods:

This was a retrospective chart review of CBT survivors diagnosed at ≤18 years of age. BMI z-scores at diagnosis and at the most recent follow-up, and concomitant endocrinopathies were abstracted from the electronic medical record. Weight status categories were classified using WHO age- and sex-adjusted BMI z-score criteria. The primary outcome was change in BMI z-score (ΔBMIz). Multivariable linear regression identified predictors of ΔBMIz, and associations with hypothyroidism, growth-hormone deficiency (GHD), or other endocrinopathy. Participants were included if BMI z-scores were available at diagnosis and at follow-up, with a minimum follow-up duration of 1 year.


Results:

The cohort included 346 survivors (57.8% male), mean age at diagnosis of 7.1 ± 4.8 years and mean follow-up of 6.1 ± 3.2 years. BMI z-score increased significantly over time from 0.47 ± 1.49 to 0.67 ± 1.28 (ΔBMIz = +0.20 ± 1.37, p = 0.007). At follow-up, weight categories were: 54.0% normal weight, 29.5% overweight, 13.9% obese, and 2.6% underweight. Common endocrinopathies included hypothyroidism (10.4%), GHD (9.5%), precocious puberty (3.2%), and hypogonadism (2.6%). In multivariable models, female sex (B=0.17, p=0.022), lower baseline BMI z-score (B=−0.34, p< 0.001), and presence of any endocrinopathy (B=0.24, p=0.021) independently predicted greater BMI increase. Tumor type, tumor location, surgery, chemotherapy, cranial radiation, age at diagnosis, and follow-up duration were not associated with ΔBMI-z.

Cranial radiation strongly predicted endocrine sequelae (OR=6.96, p=0.001), specifically hypothyroidism (OR=7.05, p=0.001) and GHD (OR=26.4, p=0.002). Longer follow-up modestly increased the likelihood of detecting any endocrinopathy (OR = 1.13 per year, p = 0.014).

Conclusions:

CBT survivors experience significant rises in BMI z-score over time. Female sex, lower baseline BMI, and endocrine dysfunction are associated with weight gain, while cranial radiation increases long-term endocrinopathy risk. Targeted endocrine management may help mitigate progressive metabolic morbidity in this high-risk population.

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