Thyroid Cancer
Cancer of the thyroid is a disease in which cancer cells are found in the tissues of the thyroid gland. The thyroid gland is at the base of the throat. It has two lobes, one on the right side and one on the left. The thyroid gland makes important hormones that help the body function normally.

Cancer of the thyroid is more common in women than in men. Most patients are between 25 and 65 years old. People who have been exposed to large amounts of radiation, or who have had radiation treatment for medical problems in the head and neck have a higher chance of getting thyroid cancer. The cancer may not occur until 20 years or longer after radiation treatment.

A doctor should be seen if there is a lump or swelling in the front of the neck or in other parts of the neck.

If there are symptoms, a doctor will feel the patient’s thyroid and check for lumps in the neck. The doctor may order blood tests and special scans to see whether a lump in the thyroid is making too many hormones. The doctor may want to take a small amount of tissue from the thyroid. This is called a biopsy. To do this, a small needle is inserted into the thyroid at the base of the throat and some tissue is drawn out. The tissue is then looked at under a microscope to see whether it contains cancer.

There are four main types of cancer of the thyroid (based on how the cancer cells look under a microscope):

• papillary
   
• follicular
   
• medullary
   
• anaplastic

The chance of recovery (prognosis) depends on the type of thyroid cancer, whether it is just in the thyroid or has spread to other parts of the body (stage), and the patient’s age and overall health. Some types of thyroid cancer grow much faster than others.

The genes in our cells carry the hereditary information from our parents. An abnormal gene has been found in patients with some forms of thyroid cancer. If medullary thyroid cancer is found, the patient may have been born with a certain abnormal gene which may have led to the cancer. Family members may have also inherited this abnormal gene. Tests have been developed to determine who has the genetic defect long before any cancer appears. It is important that the patient and his or her family members (children, grandchildren, parents, brothers, sisters, nieces and nephews) see a doctor about tests that will show if the abnormal gene is present. These tests are confidential and can help the doctor help patients. Family members, including young children, who don’t have cancer, but do have this abnormal gene, may reduce the chance of developing medullary thyroid cancer by having surgery to safely remove the thyroid gland (thyroidectomy).


Stages of cancer of the thyroid
Once cancer of the thyroid is found (diagnosed), more tests will be done to find out if cancer cells have spread to other parts of the body. This is called staging. A doctor needs to know the stage of the disease to plan treatment.

The following stages are used for papillary cancers of the thyroid:

Stage I papillary
Cancer is only in the thyroid and may be found in one or both lobes.

Stage II papillary
In patients younger than 45 years of age:

Cancer has spread beyond the thyroid.
In patients older than 45 years of age:
Cancer is only in the thyroid and larger than 1 centimetre (about 1/2 inch).

Stage III papillary
Cancer is found in patients older than 45 years of age and has spread outside the thyroid (but not outside of the neck) or has spread to the lymph nodes.

Stage IV papillary
Cancer is found in patients older than 45 years of age and has spread to other parts of the body, such as the lungs and bones.

The following stages are used for follicular cancers of the thyroid:

Stage I follicular
Cancer is only in the thyroid and may be found in one or both lobes.

Stage II follicular
In patients younger than 45 years of age:
Cancer has spread beyond the thyroid.
In patients older than 45 years of age:
Cancer is only in the thyroid and larger than 1 centimetre (about 1/2 inch).
 

Stage III follicular
Cancer is found in patients older than 45 years of age and has spread outside the thyroid (but not outside of the neck) or to the lymph nodes.

Stage IV follicular
Cancer is found in patients older than 45 years of age and has spread to other parts of the body, such as the lungs and bones.
Other types or stages of thyroid cancer include the following:

Stage I medullary
Cancer is less than 1 centimetre (about 1/2 inch) in size.

Stage II medullary
Cancer is between 1 and 4 centimetres (about 1/2 to 1 1/2 inches) in size.

Stage III medullary
Cancer has spread to the lymph nodes.

Stage IV medullary
Cancer has spread to other parts of the body.

Anaplastic
There is no staging system for anaplastic cancer of the thyroid. This type of cancer of the thyroid grows faster than the other types.

Recurrent
Recurrent disease means that the cancer has come back (recurred) after it has been treated. It may come back in the thyroid or in another part of the body.

How cancer of the thyroid is treated
There are treatments for all patients with cancer of the thyroid. Four types of treatment are used:

Surgery (taking out the cancer).
Radiation therapy (using high-dose x-rays or other high-energy rays to kill cancer cells).
Hormone therapy (using hormones to stop cancer cells from growing) .
Chemotherapy (using drugs to kill cancer cells).
Surgery is the most common treatment of cancer of the thyroid. A doctor may remove the cancer using one of the following operations:

Lobectomy removes only the side of the thyroid where the cancer is found. Lymph nodes in the area may be taken out (biopsied) to see if they contain cancer.

Near-total thyroidectomy removes all of the thyroid except for a small part.

Total thyroidectomy removes the entire thyroid.

Lymph node dissection removes lymph nodes in the neck that contain cancer.

Radiation therapy uses high-energy x-rays to kill cancer cells and shrink tumours. Radiation for cancer of the thyroid may come from a machine outside the body (external radiation therapy) or from drinking a liquid that contains radioactive iodine. Because the thyroid takes up iodine, the radioactive iodine collects in any thyroid tissue remaining in the body and kills the cancer cells.

Hormone therapy uses hormones to stop cancer cells from growing. In treating cancer of the thyroid, hormones can be used to stop the body from making other hormones that might make cancer cells grow. Hormones are usually given as pills.

Chemotherapy uses drugs to kill cancer cells. Chemotherapy may be taken by pill, or it may be put into the body by a needle in the vein or muscle. Chemotherapy is called a systemic treatment because the drug enters the bloodstream, travels through the body, and can kill cancer cells outside the thyroid.

Stage I Papillary Thyroid Cancer
Treatment may be one of the following:
Surgery to remove one lobe of the thyroid (lobectomy), followed by hormone therapy. Radioactive iodine also may be given following surgery.
Surgery to remove the thyroid (total thyroidectomy).

Stage I Follicular Thyroid Cancer
Treatment may be one of the following:
Surgery to remove the thyroid (total thyroidectomy).
Surgery to remove one lobe of the thyroid (lobectomy), followed by hormone therapy. Radioactive iodine also may be given following surgery.

Stage II Papillary Thyroid Cancer
Treatment may be one of the following:
Surgery to remove one lobe of the thyroid (lobectomy) and lymph nodes that contain cancer, followed by hormone therapy. Radioactive iodine also may be given following surgery.
Surgery to remove the thyroid (total thyroidectomy).

Stage II Follicular Thyroid Cancer

Treatment may be one of the following:
Surgery to remove the thyroid (total thyroidectomy).
Surgery to remove one lobe of the thyroid (lobectomy) and lymph nodes that contain cancer, followed by hormone therapy. Radioactive iodine also may be given following surgery.

Stage III Papillary Thyroid Cancer
Treatment may be one of the following:
Surgery to remove the entire thyroid (total thyroidectomy) and lymph nodes where cancer has spread.
Total thyroidectomy followed by radiation therapy with radioactive iodine or external beam radiation therapy.

Stage III Follicular Thyroid Cancer
Treatment may be one of the following:
Surgery to remove the entire thyroid (total thyroidectomy) and lymph nodes or other tissues around the thyroid where the cancer has spread.
Total thyroidectomy followed by radioactive iodine or external beam radiation therapy.

Stage IV Papillary Thyroid Cancer
Treatment may be one of the following:
Radioactive iodine.
External beam radiation therapy.
Hormone therapy.
A clinical trial of chemotherapy.

Stage IV Follicular Thyroid Cancer
Treatment may be one of the following:
Radioactive iodine.
External beam radiation therapy.
Hormone therapy.
A clinical trial of chemotherapy.

Medullary Thyroid Cancer
Treatment will probably be surgery to remove the entire thyroid (total thyroidectomy) unless the cancer has spread to other parts of the body. If lymph nodes in the neck contain cancer, the lymph nodes in the neck will be removed (lymph node dissection). If the cancer has spread to other parts of the body, chemotherapy may be given.

Anaplastic Thyroid Cancer
Treatment may be one of the following:
Surgery to remove the thyroid and the tissues around it. Because this cancer often spreads very quickly to other tissues, a doctor may have to take out part of the tube through which a person breathes. The doctor will then make an airway in the throat so the patient can breathe. This is called a tracheostomy.
Total thyroidectomy to reduce symptoms if the disease remains in the area of the thyroid.
External beam radiation therapy.
Chemotherapy.
Clinical trials studying new methods of treatment of thyroid cancer.

Recurrent Thyroid Cancer
The choice of treatment depends on the type of thyroid cancer the patient has, the kind of treatment the patient had before, and where the cancer comes back. Treatment may be one of the following:
Surgery with or without radioactive iodine.
External beam radiation therapy to relieve symptoms caused by the cancer.
Chemotherapy.
Radioactive iodine.
Radiation therapy given during surgery.
Clinical trials.
 

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