Thyroid Cancer (original) (raw)

Surgery. The first step in treatment for all types of thyroid cancer is surgery (see Thyroid Surgery brochure). The extent of surgery for differentiated thyroid cancers may be removing only the lobe involved with the cancer, called a lobectomy, or removing the entire thyroid, called a total thyroidectomy. The extent of surgery will depend on the size of the tumor and whether or not the tumor has spread beyond the thyroid gland. If your tumor involves both lobes of the thyroid gland or it is found on testing to have spread beyond the gland, a total thyroidectomy will be recommended. If you have thyroid cancer present in the lymph nodes of the neck (lymph node metastases), these lymph nodes can be removed at the time of the initial thyroid surgery or sometimes, as a second procedure. However, if your cancer is small, only in one lobe of the gland and if it has not spread to lymph nodes, a lobectomy may be a good option. Recent studies even suggest that if you have a small tumor measuring less than 1cm across, called papillary thyroid microcarcinoma, you may be observed very safely without surgery. If you have a total thyroidectomy, you will need to take thyroid hormone medication for the rest of your life (see Thyroid Hormone Treatment brochure). However, if you have a lobectomy, you may not need to take thyroid hormone replacement. Thyroid cancer is often cured by surgery alone, especially if the cancer is small. If your cancer is larger, if it has spread to lymph nodes, or if your doctor feels that you are at high risk for recurrent cancer, radioactive iodine may be used after the thyroid gland is removed.

Radioactive iodine therapy (Also referred to as I-131 therapy). Thyroid cells and most differentiated thyroid cancers absorb iodine so radioactive iodine can be used to eliminate all remaining normal thyroid tissue and potentially destroy residual cancerous thyroid tissue after thyroidectomy (see Radioactive Iodine brochure). The procedure to eliminate residual thyroid tissue is called radioactive iodine ablation. Since most other tissues in the body do not efficiently absorb or concentrate iodine, radioactive iodine used during the ablation procedure usually has little or no effect on tissues outside of the thyroid. However, in some patients who receive larger doses of radioactive iodine for treatment of thyroid cancer metastases, radioactive iodine can affect the glands that produce saliva and result in a dry mouth. If higher doses of radioactive iodine are necessary, there may also be a small risk of developing other cancers later in life. This risk is very small, and increases as the dose of radioactive iodine increases. The potential risks of treatment can be minimized by using the smallest dose possible. Balancing potential risks against the benefits of radioactive iodine therapy is an important discussion that you should have with your doctor if radioactive iodine therapy is recommended.

If your doctor recommends radioactive iodine therapy, your TSH level will need to be elevated prior to the treatment. This can be done in one of two ways.

The first is by stopping thyroid hormone pills (levothyroxine) for 3-6 weeks. This causes high levels of TSH to be produced by your body naturally. This results in hypothyroidism, which may involve symptoms such as fatigue, cold intolerance and others, that can be significant. To minimize the symptoms of hypothyroidism your doctor may prescribe T3 (Cytomel®, liothyronine) which is a short acting form of thyroid hormone that is usually taken after the levothyroxine is stopped until 2 weeks before the radioactive iodine treatment.

Alternatively, TSH can be increased sufficiently without stopping thyroid hormone medication by injecting a synthetic form of TSH into your body. Recombinant human TSH (rhTSH, Thyrogen®) can be given as two injections in the days prior to radioactive iodine treatment. The benefit of this approach is that you can continue taking the thyroid hormone medication and avoid possible symptoms related to hypothyroidism.

Regardless of whether you become hypothyroid (stop thyroid hormone) or use recombinant TSH therapy, you may also be asked to go on a low iodine diet for 1 to 2 weeks prior to treatment (see Low Iodine Diet FAQ), which will result in improved absorption of radioactive iodine, maximizing the treatment effect.