Treating Thyroid Cancer
Most patients with thyroid carcinoma will need to have the entire thyroid gland removed. It is important that your surgery be performed by a surgical team with a lot of experience doing these kinds of procedures.
Radioactive Iodine Therapy
Your doctor may recommend radioactive iodine therapy if the cancer is above a certain size or has spread to adjacent tissue or to distant sites in the body (metastasized). This treatment is uniquely suited for thyroid cancer because thyroid cells are the primary cells in the body that utilize iodine. Thus, using radioactive iodine therapy, which is toxic to cells that take it up, targets only thyroid cells. This therapy allows for destruction of remaining normal and abnormal thyroid tissue, including metastatic disease, and also improves the ability to perform surveillance for recurrence.
Before undergoing radioactive iodine treatment, the levels of thyroid stimulating hormone (TSH) in the bloodstream need to be high for radioactive iodine to be taken up by the cancer cells. TSH allows iodine to maximally enter any remaining thyroid cells and therefore destroy them. An appropriate rise in TSH is typically accomplished by stopping all thyroid hormone for ~ 6 weeks after surgery. Once this is achieved, you will undergo a scan with a small dose of radioactive iodine to determine if cancer cells at the distant sites absorb the iodine. If results show that the cancer cells absorb the radioactive iodine, you will undergo treatment with a larger dose in an attempt to destroy these cells.
Precautions Following Radioactive Iodine Therapy
Thyroid Hormone Medication
If your thyroid gland is removed, you will need to take thyroid hormone replacement in pill form each day to replace the hormone that is no longer being produced in your body.
The primary goal in replacing thyroid hormone for most patients with thyroid cancer is to make the TSH levels in the blood lower than the normal range, since TSH from the pituitary gland is known to stimulate tumor growth. “TSH suppression” is accomplished by giving higher than the average amounts of thyroid hormone pills. Medical studies have found that cancer is more likely to come back in individuals who do not take this therapy. It is important that you let all your physicians know that you have thyroid cancer when they check your TSH levels, because “normal” values in a patient with thyroid cancer may be inappropriate. Remember, for most patients with thyroid cancer the TSH should be lower than normal.
Chemotherapy is not very effective with papillary and follicular thyroid cancers that continue to spread throughout the body. Your doctor will discuss other treatment options with you in more detail.