Background : Several studies showed patients with coexisting Hashimoto’s thyroiditis with differentiated thyroid cancer had a few recurrences, improved survival rates, good prognosis. On the other hand, Hashimoto’s thyroiditis was an independent r...
Background : Several studies showed patients with coexisting Hashimoto’s thyroiditis with differentiated thyroid cancer had a few recurrences, improved survival rates, good prognosis. On the other hand, Hashimoto’s thyroiditis was an independent risk factor with thyroid carcinoma in another data. So, aim of this study was to compare between benign thyroid disease patients and thyroid carcinoma patients. And then, we examined what is independently associated with thyroid carcinoma.
Methods: In this retrospective study, 640 patients underwent thyroid operation were examined from January 2006 to December 2007. We divided these patients into 2 groups; group1 - 251 patients with benign thyroid disease and group2 - 389 patients with thyroid cancer. We compared age, sex, serum TSH levels, autoantobodies, existence of Hashimoto’s thyroiditis, ultrasonographic findings between two groups. And the association factor of thyroid cancer was investigated using the multiple logistic regression analysis that was adjusted for age, sex, Hashimoto’s thyroditis, increased serum TSH levels, autoantibodies, ultrasonographic findings.
Results: Group2 had higher serum TSH levels, positive rate of autoantibodies, and coexistence rate of Hashimoto’s thyroiditis than group1. In addition, group2 patients had smaller nodular sizes, lower echogenecity, higher carcification, irregular margins and more solid components than group1. The risk of diagnosis of malignancy rose in parallel with the serum TSH at presentation (p=0.0009). Logistic regression analysis revealed significantly increased adjusted odds ratios (AORs) for the diagnosis of malignancy in subjects with serum TSH levels more than 1.8mU/L (AOR 2.44(CI 1.01-5.88, p=0.047)) compared with TSH less than 0.4 mU/L. And autoantibodies (AOR 2.19 (CI 1.00-4.79, p=0.050)), microcalcifications (AOR 2.10 (CI 1.11-3.98, p=0.022)), macrocalcification (AOR 5.01 (CI 1.23-20.37, p=0.024)) and irregular margins of nodules in ultrasonographic findings (AOR 1.80 (CI 1.01-3.19, p=0.045)) were also at increased risk. On the other hand, nodule size more than 22mm (AOR 0.15 (CI 0.09-0.26, p <0.0001)) was associated with a decreased risk. No association was observed between Hashimoto’s thyroiditis and thyroid cancer.
Conclusions: Our data suggests increased serum TSH levels and presence of autoantibodies but not Hashimoto’s thyroiditis were independent risk factors of thyroid malignancy.