Thyroid autoimmunity: is really associated with papillary thyroid carcinoma?

The incidence of thyroid cancer has been greatly increasing. Several studies aimed to investigate biomarkers for prediction of thyroid cancer. Some of these studies have suggested that thyroid autoantibodies (TAb) could be used as predictors of thyroid cancer risk, but the correlation between TAb and PTC is still a matter of debate. The aim of this study is to evaluate thyroid autoimmunity and TAbs in patients with PTC and benign multinodular goiter (MNG) to investigate if TAbs and autoimmune thyroid disease (ATD) could predict thyroid malignancy. A total of 577 patients with thyroid papillary carcinoma (PTC) and 293 patients with benign MNG disease were enrolled postoperatively. Demographic features, thyroglobulin (TgAb) and thyroid peroxidase antibodies (TPOAb) and histologic outcome of the patients were evaluated. The prevalence of ATD and TgAb or TPOAb measurements was not statistically different in PTC and MNG groups. However, tumors were significantly smaller and tumor capsule invasion was seen less frequently in patients with PTC and ATD than without ATD. Patients without ATD had more advanced stage (TNM stage III/IV) tumors than with ATD. Only one of the 11 patients with distant organ metastasis had ATD. The present study demonstrated that the prevalence of ATD diagnosed even with histology or TAb positivity was not different in patients with PTC and MNG. However, having ATD might be associated with a better prognosis in PTC patients.