Latent thyroid pathology in residents of Kiev, Ukraine

Thyroid glands from 162 patients were examined for occult thyroid pathology at autopsy. The patients were residents of Kiev, aged 16 to 82 years, without known thyroid disease. Abnormalities were observed in 66 of the 162 cases (40.7%) and included nodular hyperplasia (13.6%), follicular adenoma (4.9%), and thyroiditis (9.5%). Thyroid carcinoma was found in 11.7% of cases (18 papillary microcarcinomas and one follicular oncocytic carcinoma). No cancer was found in the thyroids of patients under 35 years of age. Cancer was predominant in women, but there were no significant differences in the frequency of occult carcinoma with increased age. The neoplasms varied in size from microscopic foci to 9 mm in diameter; most (63%) were over 5 mm. The cancer incidence rate in our study was lower than that found in Finland and Japan, but higher than in most other published series. The absence of a correlation between the rather high frequency of latent thyroid cancer in autopsy data and the relatively low annual incidence of clinically evident thyroid cancer in Ukraine residents may reflect the impact of initiating factors on carcinogenesis of the thyroid. Our results suggest that environmental factors in the area of Ukraine, contaminated by the Chernobyl accident, may play an important role in the etiology of thyroid cancer, but further research is needed.