Treatment of thyroid carcinoma: emphasis on high-dose 131I outpatient therapy

There is an abundance of evidence indicating that the oral administration of sodium (13I)I-iodide is of value in the management of well-differentiated thyroid cancers. The first step in the management of thyroid cancer is near-total removal of the thyroid gland. Destroying any residual functioning thyroid tissue in the neck or metastatic tissue elsewhere in the body using (131)I after surgery decreases the risk of recurrence and death from well-differentiated thyroid cancers. The dosage of radioiodine used for this purpose varies among different centers. Until a few years ago, radioiodine therapy using >1.110 GBq (30 mCi) (131)I required hospitalization of patients to minimize radiation exposure to others. The U.S. Nuclear Regulatory Commission (USNRC) revised Title 10 of the Code of Federal Regulations (10CFR 35.75) in 1997, allowing the release of patients immediately after (131)I therapy if the total effective dose equivalent from the patient to an individual does not exceed 5 mSv (0.5 rem) in any 1 y. With this change, which became effective on May 29, 1997, a patient can be treated with a higher amount of (131)I as an outpatient and leave the premises with proper instructions to keep the radiation exposure to other individuals as low as it is reasonably achievable. The objectives of this article are to (a) briefly review the types of thyroid cancer; (b) provide an overall review of the treatment of thyroid carcinomas, follow-up of these patients, and the prognostic indicators of survival; and (c) explain the radiation safety precautions and the preventive measures that can be taken to minimize the radiation exposure of family members or helpers living with the patient and the general public at large.