Incidence of Thyroid Carcinoma Among Patients With Hyper and Hypothyroidism

Abstract

Objective: Our aim was to determine the incidence of thyroid carcinoma in patients with hyperthyroidism and hypothyroidism and to demonstrate whether hyperthyroidism is actually a protective state against carcinoma. Background: In endemic regions for goiter such as Turkey, the rate of cancer is reported to be lower among patients with hyperthyroidism than those with hypothyroidism. However, we observed in our clinic that carcinoma incidence in patients with hyperthyroidism is at least as high as those with hypo-euthyroidism. Methods: Cases of bilateral total thyroidectomy performed in the Istanbul Training and Research Hospital General Surgery Clinic between the years 2000 and 2014 were retrospectively examined. Age, gender, hormone levels, and postoperative pathological diagnoses were independently compared. Results: Data from 1200 patients was analyzed. Mean age was 49.2. Of the patients 220 (17.5%) were male and 990 (82.5%) were female; 722 of the female patients had benign pathologies and 268 had malignant pathologies, whereas 144 of the male patients had benign and 66 had malignant pathologies. Compared by age, no significant difference was detected in pathological diagnoses and hormone levels. Comparing the pathological diagnoses according to hormone levels, rate of malignancy was significantly higher in patients with hyperthyroidism than those with hypothyroidism or euthyroidism. Conclusions: Unlike what is previously accepted, hyperthyroid patients also carry a risk for thyroid carcinoma. Thus, these patients should be followed up for cancer at least as closely as those with hypothyroidism and euthyroidism.