Immune Checkpoint Inhibitor-Induced Endocrine Adverse Events in Cancer Patients at a Tertiary Care Center in Saudi Arabia

Introduction: Immune checkpoint inhibitors (ICIs) are approved to treat several types of cancer, but they may cause an exaggerated immune response. This can lead to immune-related adverse events such as endocrinopathies, which mostly affect the thyroid and pituitary gland.

Methods: A retrospective analysis was conducted on 125 cancer patients receiving ICIs (pembrolizumab, nivolumab, and ipilimumab) between July 2018 and July 2022. The study reviewed hormone test results and the clinical perspectives of patients to identify and characterize endocrine adverse events associated with ICI therapy in cancer patients.

Results: Among the 125 patients who were examined, a total of 26 patients (20.8%) encountered endocrine-related adverse effects. A total of 25 patients had thyroid dysfunction. Hypophysitis was detected in a limited cohort of two patients, along with primary hypothyroidism. A case of newly diagnosed type 1 diabetes mellitus was seen in a single patient. None of the patients had primary adrenal insufficiency or parathyroid dysfunction. The administration of pembrolizumab was shown to be associated with the occurrence of thyroid dysfunction in 18 cases, as well as two cases of hypophysitis. In contrast, nivolumab was responsible for inducing thyroid dysfunction in four cases. The remaining occurrences were attributable to combination treatment.

Conclusion: The study found an increased risk of thyroid dysfunction among cancer patients receiving ICIs, while pituitary dysfunction was a less frequent adverse effect. It is recommended that an endocrine assessment be conducted before therapy initiation and periodically afterward.