To investigate the incidence and influencing factors of thyroid dysfunction (TD) in patients with primary liver cancer (PLC) induced by PD-1 monoclonal antibodies.

Clinical data were collected from 195 PLC patients treated with PD-1. They were divided into TD group and normal thyroid function (NTF) group, and further divided into TD subgroups, the differences between groups and subgroups were analyzed.

A total of 113 of 195 (57.9%) PLC patients developed TD. The positive rate of thyroid antibody (20.6% vs. 0%, P = 0.041) and the median value of TSH (6.20 vs. 2.16 mU/L, P = 0.000) in TD group were higher than those in NTF group. Ten patients (8.8%) had the CTCAE grade of TD above grade 3, of which 2 patients died of liver failure. There were 20 patients (17.7%) in hyperthyroidism group and 93 patients (82.3%) in hypothyroidism group. The decompensated cirrhosis in hyperthyroidism group was lower than that in hypothyroidism group (33.3% vs. 65.6%, P = 0.010), and the proportion of patients who had previously received surgical treatment was higher than that in hypothyroidism group (35.0% vs. 9.7%, P = 0.003); The proportion of clinical hyperthyroidism was higher than that of clinical hypothyroidism (70.0% vs. 31.2%, P = 0.001), the proportion of decompensated liver cirrhosis in clinical hyperthyroidism group was lower than that in clinical hypothyroidism group (23.1% vs. 68.0%, P = 0.022), and the proportion of previous or combined surgical resection was much higher than that in clinical hypothyroidism group (42.9% vs. 7.1%, P = 0.018); The proportion of decompensated cirrhosis in primary TD group was lower than that in secondary TD group (36.5% vs. 83.3%, P = 0.002), and the proportion of patients using antitumor targeted drugs was higher than that in secondary TD group (73.1% vs. 45.0%, P = 0.014).

Patients with PLC had high incidence of TD after receiving PD-1 treatment, primary or subclinical hypothyroidism was the main manifestation type, which was related to the degree of disease and treatment.