Thyroid Cancer

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Once you have been diagnosed with thyroid cancer, your doctor will explain your prognosis and treatment options. A prognosis is your doctor's estimate of what will happen with your cancer, including your chance of recovery, the expected course of the cancer, and the length of time you will be ill.

Your prognosis will depend on the stage of the cancer, the type of cancer, and your overall health.

Treatment of thyroid cancer may include:

  • Surgery to remove all or part of the thyroid (thyroidectomy)
  • Radiation therapy, either external beam radiation or radioactive iodine
  • Thyroid hormone suppression therapy
  • Chemotherapy
  • In most cases of differentiated (papillary and follicular) thyroid cancer, two or more of these methods are used. For medullary thyroid cancer, most patients are treated with surgery only.

    This section contains more information on:

    • Surgery
    • Radiation
    • Hormone therapy
    • Chemotherapy
    • Recurrence
    • Surgery

      Almost all cases of thyroid cancer are treated with surgery. Many are also treated with additional methods.

      The surgery will most likely be one of the following:

      • Total thyroidectomy. The entire thyroid is removed.
      • Near-total thyroidectomy. Most of the thyroid is removed.
      • Lobectomy. Only the side of the thyroid where the cancer is located is removed. This type of surgery may be used in papillary cancers smaller than 1 centimeter (about ½ inch) that have not spread.
      • Lymph nodes in the area of the tumor or in the neck and/or chest may also be removed. Patients usually spend one to three days in the hospital for thyroid cancer surgery.

        Possible complications of the surgery include:

        • Damage to the nerves that control the vocal cords, which may cause temporary or permanent hoarseness or loss of voice
        • Irritation of larynx by intubation, which may cause temporary or permanent hoarseness or loss of voice
        • Damage to parathyroid glands, which may lower blood calcium levels and lead to muscle spasms and numbness
        • Infection of the surgical site
        • Bleeding or formation of a hematoma (blood clot in the neck)
        • If your thyroid is removed, you will take thyroid hormone replacement pills daily for the rest of your life.


          Radiation therapy uses high-energy X-rays or other types of radiation to kill cancer cells or shrink tumors. Thyroid cancer may be treated with:

          • Radioactive iodine. The patient drinks a liquid that contains radioactive iodine, which collects in thyroid tissue and kills cancer cells.
          • External beam radiation. Radiation comes from outside the body.
          • The type of radiation used depends on the type and stage of your cancer. External beam radiation is most effective for thyroid cancers that do not absorb iodine, including anaplastic thyroid cancer. It is also used if any type of thyroid cancer remains after surgery or if cancer has spread to the bones.

            External beam radiation uses a machine outside the body to send radiation toward the thyroid tumor. The rays are carefully targeted to minimize damage to healthy tissues. Like an X-ray, the procedure is painless.

            Treatments are usually delivered five days a week for five to eight weeks. On the days of your treatment, you will lie on a treatment table, and the radiation therapist will position you so the radiation reaches the correct part of your body. Once you are positioned, you cannot move until the treatment is finished. The treatment takes only a few minutes. To help you remain still, a custom-fitted plastic head or shoulder mask may be used. Each appointment takes about 30 minutes. You will be in the same position during every treatment.

            Side effects of radiation treatment may include:

            • Fatigue
            • Red, dry, tender, itchy skin, similar to a sunburn
            • Moist, weepy skin (later in treatment)
            • Mouth, teeth, and gum problems
            • Hair loss in treated area
            • Loss of appetite
            • Diarrhea
            • Frequent, uncomfortable urination
            • Reduced white blood cell count, which may increase the likelihood of infections
            • Radioactive iodine is used to destroy thyroid tissue remaining after thyroidectomy or to destroy thyroid cancer in other parts of the body, such as the lymph nodes. It has much less effect on the rest of your body. Radioactive iodine is usually given as a capsule or liquid. The thyroid or thyroid cancer absorbs the radioactive iodine.

              If radioactive iodine is used after surgery, you may be asked to discontinue your thyroid hormone medicine to make the iodine more effective. This can sometimes be uncomfortable. A newer method gives TSH, or thyroid stimulating hormone, by injection and does not require stopping thyroid medicine.

              Side effects of radioactive iodine treatment are not common. They may include:

              • Tenderness of the neck
              • Nausea or stomach irritation
              • Dry mouth or salivary gland problems
              • Dry eyes
              • Temporarily irregular periods for women
              • Women should not become pregnant for six months to a year after radioactive iodine treatment.

                Hormone therapy

                Thyroid hormone therapy uses hormones to halt the growth of cancer cells. In papillary or follicular thyroid cancer, hormone treatment may be used to lower the level of thyroid stimulating hormone, which increases the chance of recurrence. In other thyroid cancers, thyroid hormone may be used to maintain normal levels of thyroid hormone in the body.

                Hormone therapy is given as a pill. Taking thyroid hormone at the proper dose usually does not cause side effects. If the dose is too high, side effects may include heart palpitations, nervousness, insomnia, and osteoporosis (thinning of the bones).


                Chemotherapy often is used in combination with external beam radiation therapy to treat anaplastic thyroid cancer. It is usually not particularly effective in other types of thyroid cancer.

                Chemotherapy uses drugs to stop the growth of cancer cells by killing the cells or stopping them from dividing. The drugs can be given by mouth or injected into a vein or muscle. Usually, chemotherapy is given to a patient through a vein during an outpatient visit.

                Chemotherapy affects normal cells as well as cancer cells. You may experience side effects that include:

                • Nausea and vomiting
                • Loss of appetite
                • Loss of hair
                • Mouth sores
                • Diarrhea
                • Fatigue
                • Low blood count
                • Bleeding or bruising easily
                • Numbness or tingling in the hands or feet
                • Headaches
                • Darkening of the skin and fingernails
                • Recurrence

                  The chance that thyroid cancer will return depends on the stage of the original cancer. During a 10-year period after diagnosis, chances of thyroid cancer recurrence are:

                  • Stage I: 10 percent
                  • Stage II: 20 percent
                  • Stage III: 30 percent
                  • Thyroid cancers grow slowly and can return 10 to 20 years or longer after initial treatment. Thyroid cancer may come back in the area where the thyroid used to be or appear in other parts of the body.

                    If papillary or follicular cancer reappears and absorbs iodine, as most do, the cancer may be killed with large doses of radioactive iodine. If the cancer recurs but does not take up iodine, you may be treated with radiation or chemotherapy.

                    If you had medullary thyroid cancer and the cancer returns, you may or may not receive more radiation and/or chemotherapy, depending on whether the cancer is growing in a vital organ.

                    For medullary thyroid cancer, as well as both types of differentiated thyroid cancer, surgery is usually the preferred treatment for disease that recurs in the neck.

                    To watch for possible recurrence of cancer, you will probably have follow-up visits:

                    • Six months after treatment
                    • 12 months after treatment
                    • Every year after that
                    • Differentiated thyroid cancer has a lower chance of returning if thyroid stimulating hormone levels are low. Oral thyroid hormone helps keep TSH levels low while maintaining normal metabolism. This therapy, sometimes called "suppressive therapy," has few side effects.

                      For papillary and follicular thyroid cancer, the thyroglobulin level in your blood will be tested at each follow-up visit. If it begins to rise, that is a signal that the cancer may be coming back. If this happens, you will probably be tested with a neck ultrasound, perhaps radioactive iodine, as well as PET scans and/or other imaging procedures. Read more about imaging procedures in the section on testing.

                      If you had papillary or follicular cancer and your thyroid was removed, you may have at least one radioactive iodine scan, probably six to 12 months after the procedure. If it is negative, you will probably not need another. Most patients will have periodic ultrasounds of the neck.

                      If you had medullary thyroid cancer, blood levels of calcitonin and carcinoembryonic antigen will be tested periodically. If they rise, your physician may order imaging tests to find out if the cancer has returned.

                      Last reviewed on 6/4/09

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