The Chernobyl nuclear power plant accident in the former Soviet Union in 1986 exposed large numbers of people in Ukraine, Belarus and Russia to radioactive iodines, principally I-131, which concentrates in the thyroid gland. From 1998 to 2007/8, DCEG investigators conducted biennial thyroid screening examinations of individuals exposed to the accident as children (approximately 12,000 in each country). The initial report from Ukraine provides convincing evidence in support of earlier reports of a radiation-related increase in thyroid cancer among those who were children or adolescents at the time of the accident and includes individual dose estimates on all subjects. The data show a strong, approximately linear dose-response relationship. Other studies in Ukraine include individuals exposed in utero to radioiodines, who may have a raised risk of thyroid neoplasia. The relationship between radiation and autoimmune thyroiditis, follicular adenoma, and hypothyroidism have also been assessed. Future efforts will utilize national cancer registries for follow-up and various strategies for maintaining contact with these cohorts.
For more information, contact Kiyohiko Mabuchi.