Thyroid dysfunction in Chinese nasopharyngeal carcinoma after anti-PD-1 therapy and its association with treatment response.

BACKGROUND: Programmed cell death protein-1 (PD-1) blockade therapies have demonstrated efficacy in nasopharyngeal carcinoma (NPC). Thyroid dysfunction is among the most common immune-related adverse events. This study aimed to explore the clinical pattern of thyroid dysfunction and its relationship with survival marker in nonmetastatic NPC after immunotherapy. METHODS: From January 1, 2019, to December 31, 2021, 165 pairs of nonmetastatic NPC patients (165 with and 165 without anti-PD-1 immunotherapy) matched by the propensity score matching method were included in this study. Thyroid function was assessed retrospectively before the first treatment and during each immunotherapy cycle. RESULTS: The spectrum of thyroid dysfunction was different between the immunotherapy and control groups (P < 0.001). Compared with the control group, patients in the immunotherapy group developed more hypothyroidism (14.545% vs. 7.273%), less hyperthyroidism (10.909% vs. 23.636%), and a distinct pattern, biphasic thyroid dysfunction (3.030% vs. 0%). Immunotherapy also accelerates the onset of hypothyroidism, which was earlier with a median onset time difference of 32 days (P < 0.001). Patients who acquired thyroid dysfunction during immunotherapy had better complete biological response to treatment (OR, 10.980; P = 0.042). CONCLUSIONS: For nonmetastatic NPC, thyroid dysfunction was associated with better response to treatment in immunotherapy but not in routine treatment. Thyroid function could be used as a predictor for survival and should be under regular and intensive surveillance in clinical practice of anti-PD-1 immunotherapy for nonmetastatic NPC.