Systematic Review and Meta-Analysis on the Prevalence of Radiotherapy-Induced Hypopituitarism in Adults With Primary Non-Pituitary Brain Tumours.

Context: It is well recognised there is a high prevalence of pituitary dysfunction in childhood brain tumours survivors who are treated with radiotherapy. In contrast, the potential for survivors of brain tumours arising in adulthood to develop radiotherapy-induced hypopituitarism may be underestimated. The aim of this systematic review and meta-analysis is to determine the pooled prevalence of radiotherapy-induced hypopituitarism in survivors of primary non-pituitary brain tumours arising in adulthood.

Design: A systematic literature search of five databases was performed. Two reviewers independently screened potential articles and then extracted data from accepted studies. A random effects meta-analysis was performed to assess the pooled prevalence of radiotherapy-induced hypopituitarism for each hormone axis. Forest plots were created to graphically represent these estimates with 95% confidence intervals (CI). Between study heterogeneity was quantified using the I statistic.

Results: Fourteen studies comprising a total of 580 participants were included in the review. The pooled prevalence of hypopituitarism was 48% (95% CI 36.7-59.4; I = 81%) with significant heterogeneity between study results. The pooled prevalence of growth hormone (GH) deficiency was 35.2% (95% CI 24.2-47.0; I = 81.4%), gonadotropin deficiency 20.9% (95% CI 14.4-28.1, I = 63.1%), adrenocorticotrophic hormone (ACTH) deficiency 16.0% (95% CI 11.4-21.1; I = 42.6%) and thyroid stimulating hormone (TSH) deficiency 18.2% (95% CI 12.3-24.8; I = 63.5%). Heterogeneity among study results was further evaluated through a meta-regression.

Conclusion: Radiotherapy-induced hypopituitarism is common, affecting almost half of survivors with a primary non-pituitary brain tumour arising in adulthood. Protocolised endocrine surveillance is essential in this cohort to identify and treat pituitary hormone deficits in a timely manner. These patients report decreased quality of life which may be due, in part, to undiagnosed pituitary dysfunction.