Endocrine sequelae of central nervous system irradiation

Children with central nervous system (CNS) tumors who are treated with irradiation are uniquely at risk for the development of endocrinopathies due to acquired anterior pituitary and thyroid dysfunction, which can in turn negatively affect linear growth, pubertal development, metabolism, skeletal health, and quality of life. The risk for anterior pituitary dysfunction increases with the dose of radiation delivered to the hypothalamic-pituitary axis (HPA) and with the duration of follow-up. Concomitant spinal irradiation also increases the risk of primary hypothyroidism and thyroid neoplasia. Endocrine sequelae may take years to manifest, and their clinical symptoms may be indolent and nonspecific. Early recognition and treatment should lead to better long-term health outcomes and improvements in the quality of life of childhood brain tumor survivors. The radiation oncologist can help reduce the impact of long-term endocrine sequelae by understanding the HPA and thyroid dose tolerance and facilitating the early referral and timely diagnosis of at-risk patients.