The Use of Radioactive Iodine in the Treatment of Thyroid Cancer: Novel Aspects

Thyroid cancer is treated by a combination of surgical treatment in the form of thyroidectomy, administration of radioactive iodine and subsequent administration of thyroxine. The aim of radioactive iodine administration in differentiated thyroid carcinoma patients is remnant ablation, elimination of any microscopic residual disease and treatment of persistent or metastatic disease. The indications for the administration of radioactive iodine have recently changed. In particular, recent guidelines advise against the administration of radioactive iodine in low-risk differentiated follicular-derived thyroid carcinomas. Adjuvant radioactive iodine may be considered in both low–intermediate and intermediate–high risk of recurrence for follicular-derived thyroid carcinomas. Radioactive iodine is recommended in high-risk patients and patients with distant metastatic disease. A small percentage of differentiated follicular-derived thyroid carcinomas become dedifferentiated in the course of the disease, or lose avidity for radioactive iodine, making them resistant to treatment. Recently, it has become apparent that the short-term administration of kinase inhibitors to dedifferentiated thyroid carcinoma patients may restore iodine avidity and enable treatment with radioactive iodine.