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.