Thyroid Cancer Treatment for Graves' Disease

When used to treat Graves' disease, radioactive iodine therapy cures hyperthyroidism by destroying the hyperactive thyroid cells. A single dose (between 3 and 12 mCi) of radioactive iodine is given as a pill in order to treat hyperthyroidism. RAI is about 90% effective in curing the condition. For the additional 10%, a second dose of radioactive iodine is needed. Only a few percent of people fail this second dose and require surgery to remove the overactive thyroid gland.

Radioactive iodine takes several months in order to have its full effect, although symptoms should definitely improve after about four weeks. Additional anti-thyroid medications and beta blockers may be necessary to control the hyperthyroidism during this initial time period. However, because it is impossible to give just enough radioactive iodine to destroy the exact right amount of thyroid gland without causing hypothyroidism, the eventual result is usually an underactive thyroid. However, this hypothyroidism may not occur for years because there may be a small amount of hyperfunctioning thyroid tissue after treatment. Eventually this overactive remnant will burn out and you will be left with a deficiency of thyroid hormone.

Short-term side effects may include nausea and vomiting soon after treatment, which usually only lasts for a day or two. In addition, some of the RAI may be picked up by the salivary glands around the jaws and under the tongue, causing painful swelling and enlargement of these glands. This is treated by drinking plenty of fluids, sucking on lemon drops (in order to stimulate the flow of saliva) and occasionally pain medicine like aspirin or acetaminophen.

Because it may take a few weeks after the treatment dose of radioactive iodine before there is a decrease in the blood level of thyroid hormone, you are at risk for a worsening of hyperthyroidism during this period. In many people, this increased period of hyperthyroidism may not be a problem, however, for patients with heart disease or the elderly patient, this period of hyperthyroidism may put them at increased risk for a heart attack because the excess thyroid hormone may overstimulate the heart. For this reason, many practitioners prescribe antithyroid drugs for their patients who are about to undergo radioactive iodine treatment in order to prevent this "thyroid storm".

After undergoing radioiodine treatment for Graves' disease, you will need to follow certain guidelines and precautions in order to avoid potential radiation exposure to close family members and friends. These precautions should be followed for one week if you receive between 3 and 6 mCi of radioiodine, 2 weeks for 6-12 mCi and for one month if more than 12 mCi were administered. (see section on precautions and preparation for RAI scanning and treatment)