The immune checkpoint inhibitors (ICPIs) agents anti-T lymphocytes-associated antigen 4 (CTLA-4) and anti-programmed cell death protein-1 (PD-1) and its ligands (PD-L1/PD-L2) have opened a new scenario in the treatment of cancer. These agents can induce immuno-related adverse events (irAEs), which may affect the endocrine system.
The aim of this study was to analyze the occurrence and the course of endocrine irAEs in cancer patients treated with anti-PD-1 immunotherapy.
This was a retrospective, multicentre study, involving cancer patients treated with the PD-1 inhibitors nivolumab or pembrolizumab at reference Oncology Centres. One hundred and seventy-nine consecutive patients with different types of cancer (mostly non-small cell lung cancer, melanoma, kidney cancer) were included in the study. Patients had received nivolumab (70.9%) or pembrolizumab (29.1%) for 2-33 months. The study evaluated clinical data records until the established date of July 15, 2018. The primary end point was the assessment of endocrine toxicity and possible predictive factors.
Endocrine toxicity occurred in 54 out of 179 patients (30.2%) and was related to thyroid dysfunction, with the exception of one case of diabetes mellitus. Thyroid toxicity occurred mostly within 2 months from the initiation of immunotherapy (83% of cases). A pre-existing thyroid dysfunction was a significant predictor of disease flare.
Thyroid alterations are frequently associated with anti PD-1 treatment in cancer patients. Regular thyroid assessment should be performed, particularly in the first months of treatment and in patients with a pre-existing thyroid disease.