Pituitary and adrenal disorders induced by immune checkpoint inhibitors

Over the past decade, the development of ICI (immune checkpoint inhibitors) has constituted a revolution in the treatment of many cancers, but with a specific toxicity profile including endocrine IRAEs (immune-related adverse events). As the indications for these molecules are constantly increasing due to their efficacy, it is important that endocrinologists and oncologists know how to detect, manage and monitor this type of toxicity. Many guidelines and recommendations have been proposed in the last few years for the management of endocrinopathies. French guidelines on immunotherapy-related endocrine IRAEs were published in 2018, with a specific algorithm for hypophysitis and primary adrenal insufficiency (PAI), based on clinical suspicion followed by biochemical and imaging evaluation, and are still relevant today. Here we present the general pathophysiological mechanisms of these toxicities, and discuss the incidence, diagnosis, treatment, progression, management and monitoring of pituitary and adrenal disorders in patients treated by immunotherapy, with emphasis on hypophysitis, which is much more frequent than PAI with this type of molecule. We also highlight several key points, such as the need for emergency treatment by hydrocortisone with the possibility of continuing immunotherapy in these endocrinopathies, and the long-term persistence of corticotropin or adrenal deficiency in most cases, requiring specific "hydrocortisone education". These points should be kept in mind by oncologists and endocrinologists who treat and monitor patients treated by immunotherapy.