Growth hormone/insulin-like growth factor I axis in children treated for brain tumours: relationship to chemotherapy and nutrition

Auxologic and biochemical characterization of the three phases of growth failure in pediatric patients with brain tumors

Pediatric patients with brain tumors can loose 1 SD of height prior to beginning growth hormone (GH) therapy. The objectives of this study were to characterize the early growth failure, identify contributing factors and propose interventions. Five children were followed quarterly for 2 years to monitor auxological parameters, nutritional indices, and endocrine measuremnts. GH stimulation tests were done every 6 months to determine the timing of the onset of GH deficiency. The nadir for height velocity (HV) occurred 6 months after diagnosis. Poor gains in height correlated with decreased calorie count (p <0.001), poor weight gain (p <0.001), decreased BMI (p <0.001) and lowered leptin levels (p <0.001). All patients were able to secrete GH normally during this nadir of growth. Children treated for brain tumors demonstrate an early triphasic pattern of growth. Growth failure due to cachexia occurs first, then a second transient phase of normal growth is observed followed by a third phase of growth failure due to GH deficiency. Phase 1 is characterized by decreased HV, BMI, leptin levels and calorie counts. With recognition of this profile, the early growth failure might be preventable with aggressive nutritional rehabilitation.