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Table of Contents General Information About Thyroid Cancer
Stages of Thyroid Cancer
Recurrent Thyroid Cancer
Treatment Option Overview
Treatment Options by Stage
Treatment Options for Recurrent Thyroid Cancer
To Learn More About Thyroid Cancer
Get More Information From NCI
Changes to This Summary (05/23/2008)
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General Information About Thyroid Cancer
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Thyroid cancer is a disease in which malignant (cancer) cells form in
the tissues of the thyroid gland.
The thyroid is a gland at the base of the throat near the trachea (windpipe). It is shaped like a butterfly, with a right lobe and a left lobe. The isthmus, a thin piece of tissue, connects the two lobes. A healthy thyroid is a little larger than a quarter. It usually cannot be felt through the skin. The thyroid uses iodine, a mineral found in some foods and in iodized salt, to help make several hormones. Thyroid hormones do the following:
- Control heart rate, body temperature, and how quickly food is changed into energy (metabolism).
- Control the amount of calcium in the blood.
There are four main types of thyroid cancer:
Age, gender, and exposure to radiation can affect the risk of developing thyroid cancer.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor. Risk factors for thyroid cancer include the following:
Medullary thyroid cancer is sometimes caused by a change in a gene that is passed from parent to child.
The genes in cells carry hereditary information from parent to child. A certain change in a gene that is passed from parent to child (inherited) may cause medullary thyroid cancer. A test has been developed that can find the changed gene before medullary thyroid cancer appears. The patient is tested first to see if he or she has the changed gene. If the patient has it, other family members may also be tested. Family members, including young children, who have the changed gene can decrease the chance of developing medullary thyroid cancer by having a thyroidectomy (surgery to remove the thyroid).
Possible signs of thyroid cancer include a swelling or lump in the neck.
Thyroid cancer may not cause early symptoms. It is sometimes found during a routine physical exam. Symptoms may occur as the tumor gets bigger. Other conditions may cause the same symptoms. A doctor should be consulted if any of the following problems occur:
- A lump in the neck.
- Trouble breathing.
- Trouble swallowing.
- Hoarseness.
Tests that examine the thyroid, neck, and blood are used to detect (find)
and diagnose thyroid cancer.
The following tests and procedures may be used:
- Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or swelling in the neck, voice box, and lymph nodes, and anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
- Laryngoscopy: A procedure in which the doctor checks the larynx (voice box) with a mirror or with a laryngoscope. A laryngoscope is a thin, tube-like instrument with a light and a lens for viewing. A thyroid tumor may press on vocal cords. The laryngoscopy is done to see if the vocal cords are moving normally.
- Blood hormone studies: A procedure in which a blood sample is checked to measure the amounts of certain hormones released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it. The blood may be checked for abnormal levels of thyroid-stimulating hormone (TSH). TSH is made by the pituitary gland in the brain. It stimulates the release of thyroid hormone and controls how fast follicular thyroid cells grow.
The blood may also be checked for high levels of the hormone calcitonin.
- Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances, such as calcium, released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it.
- Radioactive iodine scan (RAI scan): A procedure to find areas in the body where thyroid cancer cells may be dividing quickly. Radioactive iodine (RAI) is used because only thyroid cells take up iodine. A very small amount of RAI is swallowed, travels through the blood, and collects in thyroid tissue and thyroid cancer cells anywhere in the body. Abnormal thyroid cells take up less iodine than normal thyroid tissue. Areas that do not absorb the iodine normally (cold spots) show up lighter in the picture made by the scan. Cold spots can be either benign (not cancer) or malignant, so a biopsy is done to find out if they are cancer.
- Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. The picture can be printed to be looked at later. This procedure can show the size of a thyroid tumor and whether it is solid or a fluid -filled cyst. Ultrasound may be used to guide a fine-needle aspiration biopsy.
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
- MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
- Fine-needle aspiration biopsy of the thyroid: The removal of thyroid tissue using a thin needle. The needle is inserted through the skin into the thyroid. Several tissue samples are removed from different parts of the thyroid. A pathologist views the tissue samples under a microscope to look for cancer cells. Because the type of thyroid cancer can be hard to diagnose, patients should ask to have biopsy samples checked by a pathologist who has experience diagnosing thyroid cancer.
- Surgical biopsy: The removal of the thyroid nodule or one lobe of the thyroid during surgery so the cells and tissues can be viewed under a microscope by a pathologist to check for signs of cancer. Because the type of thyroid cancer can be hard to diagnose, patients should ask to have biopsy samples checked by a pathologist who has experience diagnosing thyroid cancer.
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) and treatment options depend on the following:
- The age of the patient.
- The type of thyroid cancer.
- The stage of the cancer.
- The patient's general health.
- Whether the patient has multiple endocrine neoplasia type 2B (MEN 2B).
- Whether the cancer has just been diagnosed or has recurred (come back).
 Back to Top Stages of Thyroid Cancer
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After thyroid cancer has been diagnosed, tests are done to find out
if cancer cells have spread within the thyroid or to other parts of the body.
The process used to find out if cancer has spread within the thyroid or
to other parts of the body is called staging. The information gathered from the
staging process determines the stage of the disease. It is important to know
the stage in order to plan treatment. The following tests and
procedures may be used in the staging process:
- CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
- MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. The picture can be printed to be looked at later.
- Radioactive iodine scan (RAI scan): A procedure to find areas in the body where thyroid cancer cells may be dividing quickly. Radioactive iodine (RAI) is used because only thyroid cells take up iodine. A very small amount of RAI is swallowed, travels through the blood, and collects in thyroid tissue and thyroid cancer cells anywhere in the body. Abnormal thyroid cells take up less iodine than normal thyroid cells. Areas that do not absorb the iodine normally (cold spots) show up lighter in the picture made by the scan. Cold spots can be either benign (not cancer) or malignant, so more tests are needed to find out if they are cancer. A scan of the whole body may be done to find out the stage of the cancer.
- Lymph node biopsy: The removal of all or part of a lymph node. A pathologist views the tissue under a microscope to look for cancer cells.
- Bone scan: A procedure to check if there are rapidly dividing cells, such as cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in the bones and is detected by a scanner.
- Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
There are three ways that cancer spreads in the body.
The three ways that cancer spreads in the body are:
- Through tissue. Cancer invades the surrounding normal tissue.
- Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
- Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.
When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.
The following stages are used for papillary and follicular thyroid cancer in patients younger than 45 years:
Stage I
In stage I papillary and follicular thyroid cancer, the tumor is any size, may be in the thyroid, or may have spread to nearby tissues and lymph nodes. Cancer has not spread to other parts of the body.
Stage II
In stage II papillary and follicular thyroid cancer, cancer has spread from the thyroid to other parts of the body, such as the lungs or bone.
The following stages are used for papillary and follicular thyroid cancer in patients 45 years and older:
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| Pea, peanut, walnut, and lime show tumor sizes. |
Stage I
In stage I papillary and follicular thyroid cancer, cancer is found only in the thyroid and the tumor is 2 centimeters or smaller.
Stage II
In stage II papillary and follicular thyroid cancer, cancer is only in the thyroid and the tumor is larger than 2 centimeters but not larger than 4 centimeters.
Stage III
In stage III papillary and follicular thyroid cancer,
either of the following is found:
- the tumor is larger than 4 centimeters or the tumor is any size and cancer has spread to tissues just outside the thyroid, but not to lymph nodes; or
- the tumor is any size and cancer may have spread to tissues just outside the thyroid and has spread to lymph nodes near the trachea or the larynx (voice box).
Stage IV
Stage IV papillary and follicular thyroid cancer is divided into stages IVA, IVB, and IVC.
The following stages are used for medullary thyroid cancer:
Stage 0
Stage 0 medullary thyroid cancer is found only with a special screening test. No tumor can be found in the thyroid.
Stage I
Stage I medullary thyroid cancer is found only in the thyroid and is 2 centimeters or smaller.
Stage II
Stage II medullary thyroid cancer is only in the thyroid and is larger than 2 centimeters but not larger than 4 centimeters.
Stage III
In stage III medullary thyroid cancer:
Stage IV
Stage IV medullary thyroid cancer is divided into stages IVA, IVB, and IVC.
Anaplastic thyroid cancer is considered stage IV thyroid cancer.
Anaplastic thyroid cancer grows quickly and has usually spread within the neck when it is found. Stage IV anaplastic thyroid cancer is divided into stages IVA, IVB, and IVC.
Back to Top Recurrent Thyroid Cancer
Recurrent thyroid cancer is cancer that has recurred (come back) after it
has been treated. Thyroid cancer may come back in the thyroid or in other parts
of the body.
Back to Top Treatment Option Overview
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There are different types of treatment for patients with thyroid
cancer.
Different types of treatment are available for patients with thyroid
cancer. Some treatments are standard (the currently used treatment), and some
are being tested in clinical trials.
A treatment clinical trial is a research study meant to help
improve current treatments or obtain information on new treatments for patients
with cancer. When clinical trials show that a new treatment is better than the
standard treatment, the new
treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.
Four types of standard treatment are used:
Surgery
Surgery is the most common treatment of thyroid cancer. One of the following procedures may be used:
- Lobectomy: Removal of the lobe in which thyroid cancer is found. Biopsies of lymph nodes in the area may be done to see if they contain cancer.
- Near-total thyroidectomy: Removal of all but a very small part of the thyroid.
- Total thyroidectomy: Removal of the whole thyroid.
- Lymphadenectomy: Removal of lymph nodes in the neck that contain cancer.
Radiation therapy, including radioactive iodine therapy
Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. There are two types of radiation therapy. External radiation therapy uses a machine outside the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer. The way the radiation therapy is given depends on the type and stage of the cancer being treated.
Radiation therapy may be given after surgery to kill any thyroid cancer cells that were not removed. |
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