Some Elements in Thyroid Tissue are Associated with More Advanced Stage of Thyroid Cancer in Korean Women

Excessive exposure to heavy metals including cadmium and lead is known to have adverse effects on various types of cancer. The aim of the present study was to evaluate the associations between blood and tissue levels of heavy metals and trace elements and different stages of thyroid cancer in Korean women. Ninety-two Korean women undergoing thyroidectomy were included in this study. Blood and thyroid tissue levels of cadmium, lead, mercury, selenium, and zinc were measured, and histopathological results, cancer tumor node metastasis (TNM) stage, and cancer multifocality were assessed. The tissue levels of cadmium, selenium, and zinc were significantly higher in patients with TNM stages 3 and 4 compared to those in stage 1. The tissue level of cadmium was greater in patients with higher tumor stage (≥T2) than those with lower stage (T1). Also, the tissue levels of cadmium and zinc were higher in multifocal group than in unifocal group. A logistic multiple regression analysis showed that the odds ratio (OR) for advanced tumor stage group (≥T2) increased in those with higher tissue cadmium level after adjustment (OR = 1.397, 95 % CI = 1.078-1.811). The accumulation of cadmium in thyroid tissue may be one of important etiologic factors for the thyroid cancer progression and aggravation in Korean women.