Abstract: Objective To investigate the relationship of Hashimoto’ s thyroiditis (HT) and papillary thyroid cancer (PTC). Methods Clinical data of 6 234 patients with thyroid nodule operation were collected from January 2000 to June 2015. PTC was pathologically confirmed after operation in 1 016 cases. Patients were divided into PTC combined with HT group and PTC without HT group. The clinical features were compared and analyzed between two groups. Results (1) In 6 234 patients, 8.66% (540/6 234) patients were complicated with HT. Compared with patients without HT, there were more female patients, more younger patients and higher incidence of PTC in this group of patients. (P < 0.01). (2) In 1 016 patients with PTC, compared with patients without HT, there were more female patients combined with HT, more patients with lower average ages, and high incidence of age from 36 to 55 years old, multiple cancers were more common, higher proportion of small cancer (≤1 cm), and lower extracapsular extension ratio, lower rate of lymph node metastasis, and lower ratio of TNM stage Ⅲ/Ⅳ and lower BRAF mutation rate (P < 0.05 or P < 0.01). There was a positive correlation between the occurrence of HT and PTC (P < 0.01). Conclusion There is a positive correlation between the occurrence of HT and PTC. In patients combined with HT and PTC, there are more female ones, and whose prognosis are better.

Key words: Hashimoto disease, thyroid neoplasms, carcinoma, papillary, thyroid nodule