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Thyroid Cancer

 

Definition

Thyroid cancer is a disease that occurs when abnormal cells begin to grow in the thyroid gland. You may notice a lump in your neck and then go to your doctor. Or your doctor may notice a lump during a routine physical exam or on an imaging test that you are having for another health problem.

Thyroid cancer is usually found before the cancer has spread very far. This means that most people who are treated for thyroid cancer do very well. Treatment for thyroid cancer includes surgery, radioactive iodine treatment, thyroid hormone medicines, and in rare cases, radiation therapy or chemotherapy. After it is treated, thyroid cancer may come back, sometimes many years after treatment.

Before starting your treatment, your doctor needs to find out which of the five types of thyroid cancer you have. A biopsy can identify your type of cancer. During a biopsy, a small piece of thyroid tissue is removed, usually with a needle. The thyroid tissue cells are then examined under a microscope.

It is also important to determine the stage of your cancer. Staging is a way for your doctor to tell how far, if at all, the cancer has spread. It also helps your doctor decide what kind of treatment you need. Staging generally depends on your age and the results of tests done after you have had surgery to remove part or all of your thyroid gland. Sometimes lymph nodes in your neck may also be removed and examined to see if cancer is present.

If you have your thyroid gland surgically removed, you will probably have symptoms of hypothyroidism—a lack of thyroid hormone—and you will need to take thyroid hormone medicines for the rest of your life. These medicines help regulate your metabolism and other body functions that are normally influenced by the thyroid gland. For more information, see the topic Hypothyroidism.


Causes

Experts do not know the exact cause of thyroid cancer. But they do know that people who have been exposed to a lot of radiation—either from the environment or from medical treatment—have a greater chance of developing thyroid cancer. An occasional dental X-ray will not increase your risk of developing thyroid cancer. But past radiation treatment of your head, neck, or chest (especially during childhood) can increase your chances of developing thyroid cancer. Radiation was used from the 1920s to the 1950s to treat problems such as acne or enlarged tonsils, but it is no longer used to treat noncancerous conditions.

One rare type of thyroid cancer, which is called medullary thyroid cancer (MTC), runs in families. You can inherit a specific gene that increases your risk of developing MTC.

Most people do not have any known risk factors for thyroid cancer. If you do have risk factors, they can include:


Symptoms

Thyroid cancer can cause many symptoms, including:

Some people may not have any symptoms. Their doctors may find a lump or nodule in the neck during a routine physical exam.


Exams and Tests

In order to diagnose thyroid cancer, your doctor will ask about your medical history and do a physical exam. Thyroid cancer is most often found during a routine physical exam.

If you have a lump or nodule in your thyroid, your doctor may order a CT scan or an ultrasound to get a better look at your thyroid. If your doctor thinks that the lump or nodule could be cancerous, he or she will do a biopsy of the thyroid gland. A biopsy involves removing a piece of your thyroid, often through a needle. This test is a simple procedure that can be done in your doctor's office.

You may also have certain blood tests.

Other tests may be done before, during, or after your treatment for thyroid cancer.

In rare cases, when thyroid cancer has significantly spread, an MRI or a PET scan may be done.

If you have medullary thyroid cancer (MTC), a CT scan of the chest and belly and a bone scan may also be needed.


Treatment

You may be shocked to find out that you have thyroid cancer. You may also feel angry, scared, depressed, or anxious. There is no normal or right way to react to or cope with having cancer. Try to remember to take care of yourself and to get help when you need it.

The goal of treatment for thyroid cancer is to get rid of the cancer cells in your body. How this is done depends on your age, the type of thyroid cancer you have, the stage of your cancer, and your general health.

Most people have surgery to remove part or all of the thyroid gland. Sometimes a suspicious lump or nodule has to be surgically removed before you will know if you have cancer or not.

After surgery, you may need treatment with radioactive iodine to destroy any remaining thyroid tissue. When you no longer have all or part of your thyroid gland, you will probably need to take thyroid hormone medicines for the rest of your life. These medicines replace necessary hormones that are normally made by the thyroid gland and prevent you from having hypothyroidism—too little thyroid hormone.

Initial treatment

Your treatment for thyroid cancer may include:

Ongoing treatment

After treatment for thyroid cancer, you may need to take thyroid hormone medicine for the rest of your life to replace the hormones that your body no longer makes. You will also need follow-up visits with your doctor every 6 to 12 months. In addition to scheduling regular visits, be sure to call your doctor if you notice another lump in your neck or if you have trouble breathing or swallowing.

At your follow-up visits, your doctor may order:

Treatment if the condition gets worse

Thyroid cancer may come back (recur). If thyroid cancer does recur, it may be found during a physical exam, on an ultrasound, or as a result of increasing thyroglobulin levels. Unlike other types of recurrent cancer, recurrent thyroid cancer is often cured, especially if it has spread only to the lymph nodes in the neck. Recurrent thyroid cancer or thyroid cancer that has spread (metastasized) to other parts of the body is treated with:

Before you have a radioactive iodine scan to see if cancer cells have spread (metastasized), you will need to either stop your thyroid hormone replacement for a while or take Thyrogen.

 

This infomation was taken from the University of Michigan Health System's Health Library.