Effects of Radiation Treatment on Pituitary Gland and Hypothalamus Function.

Abstract

PURPOSE/OBJECTIVE(S)\nSinonasal tumors are a rare and aggressive type of head and neck tumor. Radiation therapy is one of the primary treatment modalities for sinonasal malignancies, yet previous studies have shown that radiation to the head and neck region can damage the pituitary gland leading to endocrine dysfunction. The purpose of this study is to determine the relationship between radiation dose and endocrine dysfunction in the hypothalamic-pituitary axis in patients undergoing radiation therapy for treatment of sinonasal and skull-based malignancies.\n\n\nMATERIALS/METHODS\nA retrospective chart review examined data from 89 adult patients receiving radiation therapy for sinonasal and skull-based malignancies at an academic institution between 2007 - 2019. Mean and max radiation doses to the hypothalamus and pituitary gland were determined from computed tomography scans. Patients were evaluated for endocrine levels before and after completion of radiotherapy. All patients were evaluated for thyroid stimulating hormone (TSH) and thyroxine (T4) levels, while a subset of patients (n\u202f=\u202f27) were also assessed for adrenocorticotropic hormone (ACTH), cortisol, prolactin, insulin-like growth factor 1 (IGF1), and testosterone levels. Endocrine dysfunction was defined as a new onset of abnormal endocrine levels following radiation therapy.\n\n\nRESULTS\nThe percentage of patients demonstrating post-radiation endocrine dysfunction in each hypothalamic-pituitary axis was as follows: TSH: 50%, T4: 43%, ACTH: 40%, Cortisol: 52%, Prolactin: 31%, IGF1: 11%, Testosterone: 38%. Logistic regression analysis indicated a significant relationship between mean radiation dose to pituitary gland and TSH dysfunction (P\u202f=\u202f0.0090), with increased dose correlated with higher rates of TSH dysfunction (Odds ratio: 1.05; 95% confidence interval: 1.01 - 1.09). Similarly, there was a significant relationship between max radiation dose to pituitary gland and TSH dysfunction (P\u202f=\u202f0.0053) with increased dose correlated with higher rates of TSH dysfunction (Odds ratio: 1.05; 95% confidence interval: 1.02 - 1.09).\n\n\nCONCLUSION\nCranial radiotherapy for the treatment of sinonasal and skull-based malignancies was accompanied by endocrine dysfunction in 64% of patients studied. Mean and max radiation dose to the pituitary gland were statistically significant parameters predicting TSH dysfunction. We recommend that clinicians regularly monitor endocrine levels in patients following radiation therapy, particularly in cases where high radiation doses are used.