Immune Checkpoint Inhibitors (ICPI) based on the efficacious anti-tumor immune response has become and integral part of a number of cancer therapies. However, their widespread application is also associated with myriad of adverse reactions affecting various organ systems. Common ICPIs include cytotoxic T lymphocyte-associated protein 4 inhibitor (CTLA-4 i), programmed death 1 inhibitor (PD-1) and PD ligand 1 inhibitor. Among the ICPIs induced immune-related adverse events, endocrine events are particularly common. Thyroid gland is the most commonly affected endocrine organ followed by the pituitary. Hypophysitis is specifically linked to anti-CTLA 4 inhibitors; while thyroid dysfunction is more common among anti-PD1 therapies. Rare endocrine involvements include diabetes mellitus and primary adrenal insufficiency and if untreated may be life-threatening. Combination therapies lead to more serious adverse effects. Although most ICPI-related endocrine dysfunction occur within 12 weeks of starting the therapy; some protracted ones may arise after months to years. While many endocrine adverse effects may disappear over time with treatment, some like central adrenal insufficiency and primary hypothyroidism tend to persist. Management of ICPI-induced endocrine dysfunction primarily involves hormone replacement with control of symptoms. This article aims to review the endocrine complications of ICPI therapy and offer guidance on screening and managing patients experiencing endocrine dysfunction in clinical practice.

Silima S Tarenia has completed DM in Endocrinology from NRSMC&H in the year 2021 in India. She is currently in the position of consultant endocrinologist at Tata Medical Center, Rajarhat, Kolkata. She has many publications in indexed journals and has also authored many chapters in textbooks. She has been serving as a reviewer in several reputed journals.