Endocrine side effects of cancer immunotherapy

Immune checkpoint inhibitors have recently become a cornerstone for the treatment of different advanced cancers. These drugs, represented mainly by monoclonal antibodies anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4), anti-programmed cell death protein-1 (PD-1) and anti-PD-1 ligand molecules (PD-L1 and L2), have the ability to reactivate the immune system against tumor cells, but can also trigger a myriad of autoimmune side effects, termed immune-related adverse events (irAEs). In particular, there are a number of endocrine-related irAEs. Current data from clinical trials show increased incidence of hypophysitis with CTLA4 inhibition and thyroid dysfunction with PD-(L)1 blockade. In addition, a few cases of type 1 diabetes mellitus and primary adrenal insufficiency have been reported. We discuss the incidence, clinical manifestations, diagnosis and management of immune-related endocrinopathies in this highly complex context of oncological patients in need of immunotherapies.