of Thyroid Cancer
Treatment for thyroid cancer is tailored to each individual and may include surgery, radiation, and or systemic therapy with precision cancer medicines, immunotherapy or chemotherapy. The specific treatment depends on the stage and genomic profile of the cancer.
Surgery: Patients with early stage thyroid cancer are curable with surgical removal of the cancer. Surgery to remove the entire thyroid is called a total thyroidectomy. Partial removal of the thyroid is called a lobectomy. The choice of procedure depends on age of the patient and the size of the cancer.
Patients who are at a high risk of cancer recurrence are also treated with total thyroidectomy, however a total thyroidectomy is associated with a greater risk of side effects. A total thyroidectomy is a very specialized procedure and is best executed by a skilled surgeon who has performed this operation many times. The thyroid is in close proximity to the voice box and there is a risk of injuring the nerve and thus function of the voice box.1
Thyroid Hormone Replacement: Regardless of whether a patient has a lobectomy or has the entire thyroid gland removed, they will receive supplemental thyroid hormone for the rest of their lives. Thyroid hormone is produced by the thyroid gland and is critical for maintaining metabolism. Supplemental thyroid hormone serves two purposes: to maintain hormone levels in the absence of a functioning thyroid and to suppress further growth of the gland and thus the cancer. The pituitary gland located in the brain produces a hormone that stimulates the thyroid to grow—called thyroid-stimulating hormone (TSH). In the presence of thyroid hormone, TSH remains low and removes the stimuli to any remaining cancer cells.
Radioactive Iodine Treatment: Iodine is a natural substance that the thyroid uses to make thyroid hormone. The radioactive form of iodine is collected by the thyroid gland in the same way as non-radioactive iodine. Since the thyroid gland is the only area of the body that uses iodine, the radiation does not concentrate in any other areas of the body. The radioactive iodine that is not taken up by thyroid cells is eliminated from the body, primarily in urine. It is therefore a safe and effective way to test and treat thyroid conditions.
Research indicates that treatment with radioactive iodine improves survival for patients with thyroid cancer that has spread to nearby lymph nodes or to distant locations in the body.2
Systemic Therapy: Precision Cancer Medicine, Chemotherapy, and Immunotherapy
Systemic therapy is any treatment directed at destroying cancer cells throughout the body. Some patients with early stage cancer already have small amounts of cancer that have spread outside the thyroid. These cancer cells cannot be treated with surgery alone and require systemic treatment to decrease the chance of cancer recurrence. More advanced cancers that cannot be treated with surgery can only be treated with systemic therapy. Systemic therapies commonly used in the treatment of thyroid cancer include:
Chemotherapy is any treatment involving the use of drugs to kill cancer cells. Cancer chemotherapy may consist of single drugs or combinations of drugs, and can be administered through a vein, injected into a body cavity, or delivered orally in the form of a pill. Chemotherapy is different from surgery or radiation therapy in that the cancer-fighting drugs circulate in the blood to parts of the body where the cancer may have spread and can kill or eliminate cancers cells at sites great distances from the original cancer. The drugs are usually given in cycles so that a recovery period follows every treatment period.
Most chemotherapy drugs cannot tell the difference between a cancer cell and a healthy cell. Therefore, chemotherapy often affects the body’s normal tissues and organs, which can result in complications or side effects. In order to more specifically target the cancer and avoid unwanted side effects researchers are increasingly developing precision cancer medicines.
Precision Cancer Medicines
The purpose of precision cancer medicine is to define the genomic alterations in the cancers DNA that are driving that specific cancer. Precision cancer medicine utilizes molecular diagnostic testing, including DNA sequencing, to identify cancer-driving abnormalities in a cancer’s genome. Once a genetic abnormality is identified, a specific targeted therapy can be designed to attack a specific mutation or other cancer-related change in the DNA programming of the cancer cells. Precision cancer medicine uses targeted drugs and immunotherapies engineered to directly attack the cancer cells with specific abnormalities, leaving normal cells largely unharmed. Precision medicines are being developed for the treatment of thyroid cancer, and patients should ask their doctor about whether testing is appropriate.3
Treatment of Thyroid Cancer by Stage
Stage I-II: Stage I-II thyroid cancers are generally confined to the thyroid, but may include multiple sites of cancer within the thyroid.
Stage III: Stage III thyroid cancer is greater than 4 cm in diameter and is limited to the thyroid or may have minimal spread outside the thyroid.
Stage III thyroid cancer is also referred to as locally advanced disease.
Stage IV: Stage IV thyroid cancer has spread beyond the thyroid to the soft tissues of the neck, lymph nodes in the neck, or distant locations in the body.
Recurrent: Thyroid cancer that has recurred after treatment or progressed with treatment is called recurrent disease.
1 Rosa Pelizzo M, Toniato A, Boschin IM, et al. Locally advanced differentiated thyroid carcinoma: a 35-year mono-institutional experience in 280 patients. Nucl Med Commun.2005;26(11):965-8.
2 Podnos YD, Smith D, Wagman LD, Ellenhorn JD. Radioactive iodine offers survival improvement in patients with follicular carcinoma of the thyroid. 2005;128(6):1072-6.