Radioactive Iodine for Thyroid Cancer
If you have thyroid cancer, your treatment may involve radioactive iodine to destroy cancer cells. Radioactive iodine (I-131) is usually given by mouth in small doses that usually will not cause problems for people who are allergic to iodine. Side effects associated with this treatment may include nausea, vomiting, pain, and swelling.
Radioactive iodine treatment (also called radioiodine therapy) uses radioactive iodine (I-131) to destroy thyroid cancer cells anywhere in the body. This treatment is usually given by mouth (liquid or capsules) in a small dose that usually does not cause problems for people who are allergic to iodine. The intestine will absorb the radioactive iodine, which flows through the bloodstream and collects in thyroid cells. Thyroid cancer cells that remain in the neck and in other parts of the body will be killed when they absorb radioactive iodine.
If the dose of radioactive iodine is low enough, patients will usually receive their treatment as an outpatient. If the dose is high, the doctor may protect others from radiation exposure by isolating the patient in the hospital during the treatment. Most radiation used in the treatment will be gone within a few days, and within three weeks, only traces of radioactive iodine will remain in the body.
Patients with medullary thyroid cancer or anaplastic thyroid cancer generally do not receive this treatment, because these types of thyroid cancer rarely respond to radioactive iodine therapy.
Side effects of radioactive iodine for thyroid cancer may include nausea, vomiting, pain, and swelling. Patients may also have dry mouth or lose their sense of taste or smell for a short period of time after receiving radioactive iodine treatment. Chewing sugar-free gum or sucking on sugar-free hard candy may help.
During treatment with radioactive iodine, patients are encouraged to drink lots of water and other fluids. Fluids help radioactive iodine pass out of the body more quickly, and the bladder's exposure to radioactive iodine will be reduced. Radioactive iodine for thyroid cancer destroys the cells that make thyroid hormone, which means that patients may need to take thyroid hormone pills to replace the natural hormone.
A rare side effect in men who received large doses of radioactive iodine for their thyroid cancer is loss of fertility. Although radioactive iodine usually does not cause loss of fertility in women, some doctors suggest that women avoid pregnancy for one year after radioactive iodine therapy.
If you are treating your thyroid cancer with radioactive iodine, it's important to be aware that another possible side effect is leukemia. Researchers have reported that a very small number of patients may develop leukemia years after treatment with high doses of radioactive iodine.