Pituitary dysfunction following cranial radiotherapy for adult-onset non-pituitary brain tumours.

ObjectiveThere are limited data concerning the evolution of radiation-induced hypopituitarism in adult-onset brain tumour (AO-BT) survivors, in part the consequence of the limited survival of many of these individuals. We aim to characterize the pituitary-related outcomes following cranial radiotherapy (cXRT) for adult-onset primary nonpituitary brain tumours. DesignWe retrospectively analysed longitudinal data of patients with AO-BT who received cXRT within a tertiary cancer referral centre. PatientsA total of 107 adults (age 400131years) followed for a median duration of 8years following cXRT. MeasurementsPrevalence of radiotherapy-induced hypopituitarism. Results944% received fractionated photon radiotherapy (median dose 54Gy), while the remaining patients received proton beam or stereotactic radiotherapy. 888% of patients developed hypopituitarism during follow-up. The frequency of GH, gonadotrophin, ACTH and TSH deficiencies was 869% (severe GHD 645%, partial GHD 224%), 346%, 234% and 112%, respectively. ACTH deficiency was clinically significant, necessitating glucocorticoid replacement, in only 103% of cases. Hyperprolactinaemia developed in 15% of patients, which was persistent in only 50% of cases. Multiple pituitary hormone deficiencies were present in 477% of patients, encountered more frequently in patients with tumours in proximity to the sella. Longitudinal data analysis revealed accumulation of hormone deficits throughout the follow-up period, with incidence of all pituitary hormone deficiencies almost doubling between years 2 and 7 of follow-up. ConclusionsPituitary dysfunction in AO-BT survivors following cXRT is a common, evolving, time-dependent phenomenon. It is important that deficits are identified early and replacement therapies introduced to optimize quality of life in these individuals, where prognosis is often guarded.