Evaluating the influence of anti-PD-1 immunotherapy combined with IMRT on thyroid dysfunction in nasopharyngeal carcinoma

Immunotherapy represents a major breakthrough in malignant tumor treatment in recent years. Anti-PD-1 immunotherapy has significantly prolonged Event-free Survival (EFS) in Nasopharyngeal Carcinoma (NPC). However, its potent anti-tumor effects can also attack normal tissues and organs, leading to immune-related adverse effects (irAE), with the thyroid being one of the most commonly affected organs. This study aims to analyze the incidence and related factors of thyroid dysfunction in NPC patients receiving anti-PD-1 immunotherapy with/without Intensity-modulated radiotherapy (IMRT), and further explore whether radiotherapy interacts with thyroid immune-related adverse reactions. 108 NPC patients receiving immunotherapy combined with chemotherapy or chemoradiotherapy were retrospectively included. Data collected included smoking status, BMI, presence of thyroid nodules, staging, treatment modality, thyroid mean dose (Dmean), percentage of thyroid volume receiving more than x Gy, pituitary mean dose (Dmean), and TSH and FT4 levels per cycle. T-tests, rank-sum tests, multivariate logistic regression analysis, ROC curves, and Cox proportional hazards models were used to evaluate the effects of anti-PD-1 immunotherapy combined with chemoradiotherapy on thyroid function. Patients with pre-treatment smoking history, thyroid nodules, and cervical lymph node metastasis were more likely to develop thyroid dysfunction (P