A risk stratification approach to screening for hypopituitarism based on pituitary radiation dose exposure in adult survivors of primary, non-pituitary brain tumours

Darran Mc Donald; Liam O; Maria Tomkins; Tara Mc Donnell; Niamh McDermott; Jack Lee; Clare Carthy; Mary Moore; Amar Agha; Donncha O; Kieron Sweeney; Stephen Mc Nally; Mohsen Javadpour; Clare Faul; David Fitzpatrick; Michael W. O; Mark Sherlock

doi:10.1530/endoabs.115.OC14

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Endocrine Abstracts (2026) 115 OC14 | DOI: 10.1530/endoabs.115.OC14

IES2025 Oral Communications Oral Communications (14 abstracts)

A risk stratification approach to screening for hypopituitarism based on pituitary radiation dose exposure in adult survivors of primary, non-pituitary brain tumours

Darran Mc Donald ^1,2 , Liam O’Connell ³ , Maria Tomkins ^1,2 , Tara Mc Donnell ^1,2 , Niamh Mc Dermott ¹ , Jack Lee ¹ , Clare Carthy ¹ , Mary Moore ¹ , Amar Agha ^1,2 , Donncha O’Brien ¹ , Kieron Sweeney ¹ , Stephen Mc Nally ¹ , Mohsen Javadpour ¹ , Clare Faul ^2,3 , David Fitzpatrick ³ , Michael W. O’Reilly ^1,2 & Mark Sherlock ^1,2

Author affiliations

¹Beaumont Hospital, Dublin, Ireland; ²Royal College of Surgeons in Ireland, Dublin, Ireland; ³St Luke’s Radiation Oncology Network, Dublin, Ireland

There is no established guidance on how best to screen non-pituitary brain tumours survivors for radiotherapy-induced hypopituitarism (RIH). We aimed to evaluate a risk stratification approach to RIH screening based on pituitary radiation dose exposure in brain tumour survivors treated with modern intensity-modulated radiotherapy (IMRT). Pituitary function was assessed in 140 brain tumour survivors (retrospective cohort n = 86 and prospective cohort n = 54). Participants were categorised into low (LD, <30Gy), intermediate (ID, 30-44.9Gy) and high (HD, >45Gy) pituitary radiation dose exposure groups. The median age at radiotherapy was 39.7 years (IQR 30.5-49.8) and follow-up interval following radiotherapy was 60.5 months (IQR 36.0-83.0). Groups comprised LD group (n = 33), ID group (n = 30) and HD (n = 74) survivors. The prevalence of GH deficiency was LD-35%, ID-30% and HD-78%. Gonadotropin, adrenocorticotrophic hormone (ACTH) and thyroid stimulating hormone (TSH) deficiency did not arise in the LD. Gonadotropin deficiency occurred in ID-3% and HD-18%. ACTH deficiency occurred in ID-16% and HD-15%. TSH deficiency occurred in ID-3% and HD-14%. A composite of gonadotropin, ACTH and TSH deficiency occurred in 0, 17 and 23% in the LD, ID and HD groups, respectively. Panhypopituitarism was only observed in the HD group (n = 3/40, 8%). Pituitary radiation dose thresholds (lowest dose at which specific hormone deficits occurred) were GH axis >12.2Gy, gonadotropin axis >37.1Gy, ACTH axis >36.9 Gy and thyroid axis >43.4Gy. In conclusion, screening for radiotherapy-induced hypopituitarism is unnecessary in LD adult brain tumour survivors (who are not GH replacement candidates). Reduced frequency of screening may be appropriate with intermediate doses.