[Endocrine adverse events of immune checkpoint inhibitors]

Immune checkpoint inhibitors (ICIs) have brought a major breakthrough in the treatment of malignant tumors. However, the use of ICIs has led to the emergence of new, previously unknown side effects in oncology. These agents disrupt immunological homeostasis and reduce T-cell tolerance, which can lead to the activation of autoreactive T-cells, causing various immune-related adverse events (irAEs). Side effects affecting endocrine organs develop relatively frequently with immunotherapy, affecting approximately 10% of patients. Any endocrine organ, or even several at the same time, can be damaged (autoimmune polyendocrine syndrome, APS). The most commonly affected organs are the thyroid and pituitary glands, but the adrenal glands, pancreas, and parathyroid glands can also be affected. The treatment of endocrine side effects differs fundamentally from that of other irAEs in three ways: highdose corticosteroid treatment is not required (except for hypophysitis causing visual complaints and thyrotoxic crisis); damage to endocrine organs is usually permanent, requiring lifelong hormone replacement; permanent discontinuation of ICI therapy is usually not necessary even in severe cases, as it is of no benefit due to the already established irreversible damage. Our aim is to review endocrine adverse events caused by ICIs, their symptoms, diagnosis, and provide guidance on the management of these adverse events.