Endocrine-related adverse events in a large series of cancer patients treated with anti-PD1 therapy

Purpose: Immune checkpoint inhibitors have opened a new scenario in the treatment of cancer. These agents can elicit adverse events, which may affect different systems and organs, including the endocrine system. The aims of this study were to evaluate the impact of the anti-PD-1 molecules nivolumab and pembrolizumab on endocrine toxicity and on patient outcome. Methods: A retrospective and multicentre study was designed, which involved a total of 251 patients affected by different tumors (mostly non-small cell lung cancer, 68.92% and melanoma, 24.30%) and treated with the PD-1 inhibitors nivolumab (61.35%) or pembrolizumab (38.65%) for up to 60 months. Clinical and biochemical data were recorded until July 31, 2020. Results: Endocrine toxicity occurred in 70 out of 251 patients (27.89%). It was mostly related to thyroid dysfunction and in 75% of cases occurred within 6 months from the beginning of therapy. A previous endocrine morbidity and female gender were predictors of endocrine toxicity. There was no association between endocrine dysfunction and patient outcome. However, when all toxicities (i.e., endocrine and non endocrine) were considered, a significant association with progression-free survival and overall survival was found. Conclusions: Thyroid alterations are frequently observed in cancer patients treated with anti PD-1 drugs, particularly in women and in the presence of a previous endocrinopathy. We suggest that regular thyroid assessment should be performed in these patients, especially in the first months of therapy. Finally, the onset of side effects, related to anti PD-1 agents, appears to be associated with a better outcome.