Radiation associated hyperthyroidism in patients with gynecological malignancies.

To determine the effect of abdominal and/or pelvic irradiation for gynecological malignancies on the later development of hyperthyroidism, 1,884 medical records of the patients diagnoses as carcinomas of cervix and corpus uteri, and of ovary were reviewed. Among 1,269 patients with radiation therapy, 5 patients developed hyperthyroidism after irradiation to the abdomen and/or pelvis. This is a statistically significant increase when compared with an epidemiological study. Radiation dose to the thyroid was estimated to be 30 to 200 rads. Two other patients who were irradiated to the nose or supraclavicular region in addition to the abdomen also developed hyperthyroidism. However, none of 581 patients without radiation therapy became hyperthyroid. The results indicate that radiation therapy for treatment of gynecological malignancy gives a significant radiation exposure with an increase in the incidence of subsequent hyperthyroidism.