Treatment depends on the type of cancer and the stage at the time of treatment.
A lobectomy (hemithyroidectomy) alone is sufficient treatment for benign conditions while for thyroid cancer it is better to remove the whole gland. The surgeon may also remove some of the lymph nodes in the neck to check whether any cancer cells have spread. There is a small risk that surgery may affect your parathyroid glands (which control the calcium in your body) or your voice. Usually this is temporary but in some cases the change may be permanent. Ask your surgeon to explain the risks to you beforehand. National guidelines recommend that your surgery is performed by an experienced endocrine or head-and-neck surgeon who regularly does thyroid and parathyroid surgery and who is working as part of a Multi-Disciplinary Team (MDT). (See: Your Guide to Thyroid Surgery.)
After surgery you may be treated with radioactive iodine, known as radioactive iodine ablation (RAI ablation). You will not be treated with RAI ablation if you still have half your thyroid in your neck, or if your risk of the cancer recurring is very small. Normal thyroid cells and thyroid cancer cells are unique because they are the only cells in the body to store iodine. This means radioactive iodine can be used to treat thyroid cancer. The radiation in the iodine destroys the thyroid cells. There are small risks associated with RAI ablation, such as dry mouth, altered taste and a minimal risk of other cancers which should be discussed with you before consent. After RAI ablation, patients can usually be monitored simply by an examination of the neck, blood tests and/or scans to see if the cancer is cured.
Currently there are two regimens used to prepare patients for RAI ablation: (1) recombinant TSH and (2) thyroid hormone withdrawal. Both approaches raise the level of TSH, which encourages the remaining thyroid cells, whether they are normal or cancerous, to take up the radioactive iodine very effectively.
- Thyroid hormone withdrawal – three to four weeks before RAI, your doctor will ask you to stop thyroid tablets. This will help any remaining thyroid tissue to take up radioactive iodine more efficiently. You may experience symptoms of hypothyroidism such as tiredness, lethargy, dry skin etc.
- Recombinant TSH (rhTSH) – two injections of recombinant TSH will be given on the two days before I 131 ablation. The advantage of this method is that you can continue levothyroxine treatment till ablation, and will not have to experience the discomfort sometimes associated with stopping levothyroxine.
Radioactive iodine treatment is usually given in the form of a capsule. You may need to stay in hospital for a few days to avoid exposing other people to radioactivity. Women need to avoid pregnancy for 1 year after radioiodine treatment.
Levothyroxine is given after surgery to replace the thyroid hormone the thyroid gland normally produces. Thyroxine is required in all patients who undergo a total thyroidectomy. Occasionally levothyroxine is required after a lobectomy. You may be prescribed a higher than normal dose of thyroxine in order to suppress TSH. This is in order to suppress the blood TSH level, as a high TSH can cause any remaining thyroid cancer cells to grow.