Radioiodine Treatment of Differentiated Thyroid Carcinoma: The Experience at Seoul National University Hospital

Radioactive iodine therapy has played an important role in the management of differentiated thyroid cancer (DTC) since specific accumulation of iodide in the thyroid gland was initially reported. The incidence of thyroid cancer is increasing in many countries including Korea. Conventional RIT has an effect on the treatment of metastatic thyroid cancer. To obtain the effects of I-131 therapy, tumors must accumulate iodide. However, about 20-30% of thyroid cancers do not accumulate iodide; they have a poor prognosis compared to DTC. For such cases, there are several methods available to increase the effects of RIT. One is by increasing the administration dose to the maximal safe dose to increase the delivery of I-131 to the tumor. Another is using retinoic acid to induce re-differentiation of cancer cells and to restore the accumulation of iodide. By such efforts, the clinical outcome of thyroid cancer can be improved. Historically, radioiodine therapy was started at the Seoul National University Hospital in 1960 when the “Radioisotope Clinic” was opened; this service has played a central role in nuclear medicine practice in Korea. In this paper, we summarized the data and experience with I-131 treatment on recurrent/metastasis of DTC at the Seoul National University Hospital.