Hypopituitarism After Cranial Irradiation for Meningiomas: A Single-Institution Experience

Purpose: Patients undergoing cranial irradiation are at high risk for development of subsequent pituitary deficiencies. Patients with meningiomas can expect to live many years after treatment and are therefore particularly vulnerable to long-term sequalae of radiation therapy (RT). The purpose of this study was to determine the rates and timing of onset of pituitary dysfunction across each hypothalamic-pituitary axis in patients with meningiomas in the sellar region. Methods and Materials: Data from 74 patients with meningiomas in the sellar or perisellar region who underwent RT between 2001 and 2017 at a single academic center were analyzed. Dose-volume histograms were generated to determine the dose of radiation to the pituitary gland. Pituitary function tests were evaluated before and after completion of RT. Results: There was a 20% risk for new hypopituitarism across any hypothalamic-pituitary axis after RT at a median follow-up of 43 months. Identified rates of dysfunction across each axis were 24% for thyroid and adrenal, 19% for growth hormone, and 10% for gonadal. Median time to develop deficiencies ranged from 11 months for growth hormone deficiency to 32 months for adrenal insufficiency. Deficiencies were likely to be correlated, with increased risk for thyroid dysfunction in patients with adrenal, gonadal, or prolactin deficiencies (P < .05). On univariate analysis, mean dose to the pituitary gland and male sex were associated with increased risk for post-RT thyroid deficiency (P = .01 and P = .004, respectively). There was no difference in rates of hypothyroidism after protons compared with photons (P = .14). Conclusions: Cranial irradiation for sellar meningiomas carries a risk for subsequent hypopituitarism that appears to be dose dependent and may occur years after completion of RT. Growth hormone deficiency and gonadal dysfunction were likely underestimated here secondary to a lack of routine testing. Given the favorable tumor prognosis in this patient population, early and long-term endocrine follow-up is warranted. (C) 2019 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.