Samuel L. Gargill

Treatment of thyroid carcinoma with radioactive iodine (I131)

Abstract 1.1. Eleven cases of carcinoma of the thyroid gland have been studied. Evaluation of the therapeutic efficacy of radioactive iodine (I 131 ) in six cases is presented. In one patient with papillary adenocarcinoma of the thyroid gland and a solitary metastasis to the lung resolution of the pulmonary metastasis followed treatment with radioactive iodine, I 131 . The therapeutic effects of radioactive iodine have been considered to be worthwhile in two other cases while in the remaining three cases no improvement was noted. 2.2. Following I 131 tracer studies total thyroidectomy was carried out in two of the remaining five cases and hemithyroidectomy in three cases. I 131 distribution studies or autoradiographs showed no evidence of increased uptake or localization of I 131 in the tumor tissue. Therapeutic doses of I 131 therefore were not administered. 3.3. Myxedema was induced in each of the six patients treated with radioactive iodine by one or more doses. In two patients thyroidectomy was attempted but was not feasible. In three others total thyroidectomy apparently had been accomplished previously. In each instance tracer studies showed uptakes in the thyroid gland region in the euthyroid range. The total dose in each patient ranged from 20 to 209 millicuries; the retention in the thyroid gland was 5 to 24 millicuries. 4.4. No serious adverse effects of I 131 have been observed. Transient thyroiditis and radiation sickness occurred in three of six patients after therapeutic doses. In one patient six months after 108 millicuries of I 131 a significant decrease in hemoglobin and red blood count was found. 5.5. Radioactive iodine is an important therapeutic agent in the treatment of selected instances of thyroid carcinoma.