Abstract
BACKGROUND: Oxidative stress is commonly accrued in thyroid tissue during hormone synthesis. OBJECTIVES: We aimed to examine oxidative stress in patients with thyroid cancer, benign thyroid nodules, and healthy individuals. METHODS: In this study, 138 individuals were involved. Among the selected participants, 108 had thyroid nodules, including 30 papillary thyroid cancer (PTC), 30 follicular thyroid cancer (FTC), six anaplastic thyroid cancer (ATC), 12 medullary thyroid cancer (MTC), and 30 benign nodules. In addition, 30 individuals were selected as a healthy control group. The levels of total antioxidant capacity (TAC) and total oxidant status (TOS) of thyroid tissue were measured using the ELISA method, and the oxidative stress index (OSI) was calculated. RESULTS: The TAC level was significantly lower in MTC and FTC subtypes than in controls. The TOS level was considerably higher in the MTC group than in the control and benign nodule groups. The TOS level was not changed in other groups. The OSI was considerably higher in MTC and FTC subtypes. The TAC and OSI in benign nodules were significantly lower and higher than those of controls, respectively. The OSI was higher in female patients than in males. CONCLUSIONS: The OSI can not be considered a diagnostic biomarker for benign nodules and MTC. The diverse oxidative stress status between genders may be related to the elevated cancer incidence in females.