Endocrine Abstracts

Introduction: Radiation-induced hypopituitarism has been well-described in childhood-onset brain tumour survivors, however in adults has received less attention. The aim of this study was to assess the pituitary-related outcomes following cXRT in adults with extra-sellar gliomas.

Methods: We retrospectively collected longitudinal data regarding pituitary-related outcomes from medical records of 59 patients, diagnosed with extra-sellar gliomas in adulthood, for the entire duration of their endocrine follow-up. Patients were referred to endocrinology from a tertiary cancer referral centre. GH and HPA axes were assessed by ITT and/or GST, while gonadotropin, TSH and prolactin status were evaluated using basal values of the relevant anterior pituitary hormones.

Results: patients (32 males) diagnosed with gliomas (astrocytoma, oligodendroglioma, glioblastoma and ependymoma) were assessed. 54.2, 35.6 and 10.2% of tumours were localised in the anterior, middle and posterior cranial regions respectively. All patients received photon external beam cXRT (mean dose 53.3±6.0Gy, mean number of fractions 28.7±3.3). Patients’ mean age at cXRT was 41.2±10.9 years and the mean duration of follow-up was 8.7±5.1 years. 76.3% of patients had brain surgery, while 54.2% received chemotherapy. The GH was the most commonly affected axis (severe GHD 55.9%, partial GHD 23.7%), followed by LH/FSH, ACTH and TSH deficiency (23.7, 17 and 6.8% respectively). Clinically significant ACTH deficiency necessitating glucocorticoid replacement was only present in two patients (3.4%). Hyperprolactinaemia was observed in 6 patients (10.2%), which was persistent in one case only. Longitudinal data analysis revealed gradual increase in the prevalence of pituitary hormone deficits throughout the follow-up period.

Conclusions: We observed high prevalence of pituitary dysfunction in adults with extra-sellar brain tumours following cXRT, which was comparable with the rates seen in childhood-onset brain tumour survivors. Long-term surveillance of these individuals in endocrine centres with appropriate expertise is required, given the evolving nature of radiation-induced hypopituitarism.