The American Thyroid Association recommends RAI therapy in anyone planning pregnancy for greater than six months from the time of diagnosis. Radioactive iodine is not safe for pregnant patients and so pregnancy should be avoided while Graves’ disease is present, and treatment is ongoing. Radioactive iodine is also a good option for poor surgical candidates. If there is significant heart and lung disease which puts a patient at high risk for surgical therapy, then radioactive iodine is a viable option. Likewise, if there has been previous operation on the neck or radiation for head and neck cancer, this increases thyroidectomy risk and radioactive iodine may be a good option for these patients.
Risks to Consider with RAI Treatment
One of the reasons to consider other options are the risks of radioactive iodine therapy. There is a small risk of thyroid storm with RAI treatment. Therefore, it is recommended that normal thyroid hormone levels be established with antithyroid medications prior to treatment with RAI. Response rates of RAI range from 60-86%. A typical dose of radioactive iodine therapy is 10-15 millicuries.
RAI Increases Risks of Certain Cancers
While some studies have found no increase in overall cancer risk after RAI treatment for hyperthyroidism, there is noted a trend towards increased risk of thyroid, stomach and kidney cancer and further research in this area is needed. Recent reports do show an increase in risk of death from breast cancer, kidney cancer and stomach cancer in patients who have prior treatment with RAI for Graves’ disease. Most people respond to RAI therapy with normalization of their thyroid function levels within four to eight weeks. In some patients this may take anywhere from two to six months. Sometimes the thyroid gland remains palpable or visible even after successful RAI therapy.
What If RAI Doesn’t Resolve My Hyperthyroidism?
If hyperthyroidism persists after six months following radioactive iodine therapy, retreatment with more radioactive iodine or thyroidectomy is recommended. Radioactive iodine can shrink goiters by 20-50% over the course of one to two years. One of the reasons to potentially avoid radioactive iodine is there is a 20% incidence of permanent dry mouth. This is a very bothersome symptom to these patients and unfortunately there is not much help for that condition if it occurs. This is definitely a reason to consider other options, particularly if the patient has dry mouth tendencies prior to the onset of Graves’ disease. Radioactive iodine treatment also makes subsequent surgeries slightly higher risk and anyone who has had RAI in the past should make sure that their thyroid surgeon is experienced and high-volume to decrease these complication risks.