The endocrine impact of immunotherapy: audit and future service implications

Abstract

Aim
To assess thyroid immune-related adverse events (irAEs) in patients receiving immune checkpoint inhibitors (ICIs) and estimate future endocrine service burden.

Methods
A retrospective audit was conducted of patients who received ICIs at St James’s Hospital from July to December 2022. Data included cancer type, ICI regimen, thyroid function test (TFT) abnormalities, and levothyroxine initiation. Management was evaluated against European Society of Endocrinology (ESE) guidelines. Prescribing data from Q3/4 2024 was used to project future case numbers.

Results
Among 96 patients, 10 (10.4%) developed thyroiditis and 9 (9.4%) hypothyroidism without prior thyroiditis. 46 (47.9%) had other TFT abnormalities. 9 of 11 (82%) of those started on levothyroxine were appropriately managed. Recent ICI prescribing showed a 329% increase in use, projecting approximately 280 cases of abnormal TFTs per 6-month period going forward.

Discussion/Conclusion
These findings support the need for proactive monitoring, guideline adherence, and strengthened endocrine-oncology collaboration to manage rising clinical demand.