Abstract

Abstract

Objective: This prospective study investigates the relationship between Hashimoto's Thyroiditis (HT) and thyroid cancer (TC) in patients with thyroid nodules (TNs). Methods: We prospectively examined 2100 patients with 2753 TNs between January 5, 2010 and August 15, 2013. A total of 2023 patients with 2669 TNs met the inclusion criteria of TN >5 mm and age >18 years (y). Each patient had blood drawn prior to fine-needle aspiration biopsy (FNAB) for the following measurements: TSH, free T4, free T3, thyroid peroxidase antibody (TPO Ab), and antithyroglobulin antibody (TgAb). Diagnosis of TC was based on pathology analysis of thyroidectomy tissue. Associations of TC with the independent variables were determined by univariate and multivariate logistic regression analysis and reported as adjusted odds ratio (OR) with 95% confidence interval (CI). Results: 248 malignant nodules were found in 233 patients. There was an association of TC with both increased serum TgAb concentration and age <45y. An elevated serum TgAb concentration was found in 10.2% of patients (182 of 1790) with benign nodules as compared to 20.6% of patients (48 of 233) with malignant nodules (p=<0.0001). TgAb (OR=2.24: CI=1.57, 3.19) and TSH >1 uIU/ml (OR (95% CI)) OR: 1.49 (1.09, 2.03) were significant predictors of TC in multivariate analysis controlling for age and gender. TC was not associated with serum concentrations of TPO Ab. Conclusion: In patients with TN, elevated serum concentration of TgAb and TSH >1 uIU/ml are independent predictors for TC. The association between HT and TC is antibody specific.