Late endocrine sequelae after radiotherapy of pediatric brain tumors are independent of tumor location

Abstract

Introduction: Irradiation of brain tumors (BT) in children can lead to the loss of pituitary function, predominantly manifesting as deficiencies in GH and ACTH. Objective: To assess the incidence and nature of pituitary deficiency in relation to initial tumor location in children after radiotherapy of BT. Methods: Twenty survivors (16 males and 4 females) of radiation-treated BT aged 1.4–10.9 (median 3.6) yr at diagnosis were studied, 10 with supratentorial and 10 with infratentorial BT. Radiation doses to the hypothalamus-pituitary (HP) area ranged from 30 to 54 (median 45) Gray. Follow-up was 9.4–16.9 (median 12.2) yr. Basal pituitary hormone levels were measured every 6 months. When growth failure became evident or pituitary deficiency was suspected, provocation tests of the HP axis were performed to assess GH, ACTH, and TSH function. Results: GH deficiency (GHD) developed in 17/20 (85%) children. In 10 patients, it occurred 4 yr after radiotherapy and in 2, 11 and 12 yr after radiotherapy. Six (30%) patients developed secondary hypothyroidism and 4 (20%) developed ACTH deficiency. Precocious puberty occurred in 2 girls. The course of development and the severity of hormone deficiencies were similar for supratentorial and infratentorial tumors. Conclusion: The major hormonal effect of BT irradiation in children is GHD, which may sometimes take more than 10 yr to manifest. We confirm findings by others that ACTH insufficiency occurs less frequently in children than reported for adults. Tumor location has no prognostic significance regarding the loss of HP function.