Radiation exposure and thyroid cancer.

There are abundant experimental and clinical data to associate radiation exposure and thyroid cancer. The incidence of thyroid cancer increases with increasing doses of thyroidal radiation from 6.5 rads to 1,500 rads, but higher doses tend to destroy the gland and are associated with hypothyroidism rather than cancer. The peak occurrence of thyroid tumors is between five and 30 years after exposure, but a person may develop thyroid tumors as long as 50 years after irradiation. Multiple thyroidal lesions or disorders, including adenomas, thyroditis, and hypothyroidism as well as malignant neoplasms, can occur after radiation exposure. It is imperative, therefore, to study carefully all patients with a history of radiation exposure to the gland and to observe them carefully for life. Suggestions are made for the management of thyroid disease in these patients.