The thyroid is a gland at the base of the throat beneath the larynx (voice box). The thyroid makes hormones that help regulate heart rate, blood pressure, body temperature, weight, and calcium levels. A healthy thyroid is a little larger than a quarter. The thyroid has two parts (called lobes).
There are four main types of thyroid cancer:
The four types are based on how the cancer cells look when viewed under a microscope.
The source for this information is the National Cancer Institute.
Several factors influence the risk of developing thyroid cancer:
- Age: Most people with thyroid cancer are over age 45. Most people with anaplastic thyroid cancer are over age 60.
- Being female: In the United States, women are almost three times more likely than men to develop thyroid cancer.
- Family history of goiters or colon growths: A small number of people with a family history of having goiters (swollen thyroids) with multiple thyroid nodules are at risk for developing papillary thyroid cancer. Also, a small number of people with a family history of having multiple growths on the inside of the colon or rectum (called familial polyposis) are at risk for developing papillary thyroid cancer.
- Family history of medullary thyroid cancer: Medullary thyroid cancer sometimes runs in families. A change in a gene called RET can be passed from parent to child. Nearly everyone with the changed RET gene develops medullary thyroid cancer.
- Personal health history: People with a goiter or benign thyroid nodules have a higher risk of thyroid cancer.
- Radiation exposure: People exposed to high levels of radiation are much more likely than others to develop papillary or follicular thyroid cancer. (Routine diagnostic x-rays such as dental x-rays or chest x-rays use very low doses of radiation. Their benefits usually outweigh the risks. Talk with a dentist and doctor about the need for each x-ray and ask about the use of shields to protect other parts of the body.)
Early thyroid cancer often does not have symptoms. But as the cancer grows, symptoms may include the following:
- A lump in the front of the neck
- Hoarseness or voice changes
- Pain in the throat or neck that does not go away
- Swollen lymph nodes in the neck
- Trouble swallowing or breathing
These symptoms could be related to other health problems such as an infection or a benign goiter. A person with any of these symptoms should see a health care provider so the problem can be diagnosed and treated as early as possible.
Currently, there are no screening methods for thyroid cancer.
If a person has symptoms that suggest thyroid cancer, their doctor may order one or more of the following tests:
- Physical exam: The doctor feels the thyroid for lumps (nodules), and also checks the neck and nearby lymph nodes for growths or swelling.
- Blood tests: Doctors check for specific substances in the blood, such as abnormal levels of thyroid-stimulating hormone (TSH). Too much or too little TSH means the thyroid is not working well. Doctors check for specific substances in the blood that indicate cancer is present.
- Ultrasound: This procedure uses high-energy sound waves bounced off internal tissues or organs to make echoes. The echoes form a picture of body tissues called a sonogram. The picture can show thyroid nodules that are too small to be felt. The doctor uses the picture to learn the size and shape of each nodule and whether the nodules are solid or filled with fluid. Nodules that are filled with fluid are usually not cancer. Nodules that are solid may be cancer.
- Thyroid scan: In this procedure, the patient swallows a small amount of a radioactive substance, and it travels through the bloodstream. Thyroid cells that absorb the radioactive substance can be seen on a scan. Nodules that take up more of the substance than the thyroid tissue around them are called "hot" nodules. Hot nodules are usually not cancer. Nodules that take up less substance than the thyroid tissue around them are called "cold" nodules. Cold nodules may be cancer.
- Biopsy: The doctor removes tissue to look for cancer cells. A biopsy is the only way to know for sure if cancer is present. Two types of biopsy are used to diagnose thyroid cancer:
- Fine-needle aspiration: This is the most common type of biopsy. The doctor removes a sample of tissue from a thyroid nodule with a thin needle. An ultrasound device can help the doctor see where to place the needle.
- Surgical biopsy: If a diagnosis cannot be made from fine-needle aspiration, a surgeon removes the whole nodule during an operation. If the doctor suspects follicular thyroid cancer, a surgical biopsy may be needed for diagnosis.
To plan the best treatment, doctors need to learn the stage (extent) of the disease. Staging is the process of finding out whether the cancer has spread, and if so, to what parts of the body. Staging may involve one or more of the following tests:
- Chest x-ray: This is 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.
- CT scan: Doctors often use CT scans to take pictures of tissue inside the body. An x-ray machine linked to a computer takes several pictures. The pictures may show whether cancer has spread to lymph nodes, other areas in the neck, or the chest.
- Magnetic resonance imaging (MRI): This procedure uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body.
- Ultrasound: An ultrasound exam of the neck may show whether cancer has spread to lymph nodes or other tissues near the thyroid.
- PET scan: Doctors use a PET scan to find cancer that has spread. The patient receives an injection of a small amount of radioactive sugar. A machine makes computerized pictures of the sugar being used by cells in the body. Cancer cells use sugar faster than normal cells, and areas with cancer look brighter on the pictures.
Stages of Thyroid Cancer
The following stages are used for papillary and follicular thyroid cancer in patients younger than 45 years:
Stage I: The tumor may be 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: The tumor may be any size and cancer has spread from the thyroid to other parts of the body, such as the lungs or bone, and may have spread to lymph nodes.
The following stages are used for papillary and follicular thyroid cancer in patients 45 years and older:
Stage I: Cancer is found only in the thyroid and the tumor is two centimeters or smaller.
Stage II: Cancer is only in the thyroid and the tumor is larger than two centimeters but not larger than four centimeters.
Stage III: The tumor is larger than four centimeters and only in the thyroid, or the tumor is any size and cancer has spread to areas close to the thyroid, such as lymph nodes, the trachea, or the larynx.
Stage IV: The tumor is any size and cancer has spread to other areas of the body.
The following stages are used for medullary thyroid cancer:
Stage 0: Cancer is found only with a special test. No tumor can be found in the thyroid.
Stage I: Cancer is found only in the thyroid and is two centimeters or smaller.
Stage II: The tumor is larger than two centimeters and only in the thyroid; or the tumor is any size and has spread to tissues just outside the thyroid, but not to lymph nodes.
Stage III: The tumor is any size, has spread to lymph nodes near the trachea and the larynx, and may have spread to tissues just outside the thyroid.
Stage IV: The tumor is any size and the cancer has spread to other areas of the body.
Anaplastic thyroid cancer is considered stage IV. This type of thyroid cancer grows quickly and usually spreads within the neck before it is diagnosed.
At Huntsman Cancer Institute, thyroid cancer is treated by a team of specialists, including otolaryngologists (doctors who specialize in diseases of the head and neck), endocrinologists (doctors who specialize in hormone-related problems), surgeons, medical oncologists, radiation oncologists, social workers, dietitians, and other professionals.
People with thyroid cancer have many treatment options:
- Thyroid hormone treatment
- Radiation therapy, including radioactive iodine
- Clinical trials
The treatment that's right for each patient depends on many factors:
- Type of thyroid cancer (papillary, follicular, medullary, or anaplastic)
- Size of the nodule
- Age of the patient
- Whether the cancer has spread
This is the most common treatment for thyroid cancer. One of the following procedures may be used:
- Lobectomy: This procedure removes the lobe of the thyroid in which cancer is found. Biopsies of lymph nodes in the area may be done to see if they contain cancer.
- Near-total thyroidectomy: This procedure removes all but a very small part of the thyroid.
- Total thyroidectomy: This procedure removes the whole thyroid.
- Lymphadenectomy: This procedure removes lymph nodes in the neck that contain cancer.
Learn more about this surgery and possible side effects in our factsheet about thyroidectomy.
This treatment uses drugs to prevent the body from making thyroid-stimulating hormone (TSH), a hormone that can increase the chance that thyroid cancer will grow or come back (recur) after treatment.
Also, because cancer treatment stops thyroid cells from growing, the body is not able to make enough thyroid hormone. Patients must take a medication to replace the thyroid hormones. Learn more about this in our factsheet thyroid hormone replacement therapy.
This treatment uses high-energy x-rays or other types of radiation to kill cancer cells or to keep cancer cells 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.
Radioactive Iodine (RAI) Therapy
Follicular and papillary thyroid cancers are sometimes treated with RAI therapy. This treatment is taken by mouth, either as a liquid or in small pills. Only thyroid cells absorb iodine. The radioactive iodine destroys thyroid tissue and cancer cells that remain after surgery, without harming other tissue.
This treatment uses drugs to destroy or control cancer throughout the body. Learn more about this treatment in our introduction to chemotherapy video.
These studies discover and evaluate new and improved cancer treatments. Patients are encouraged to talk with their doctors about participating in a clinical trial or to ask any questions regarding research studies. For more information, also visit HCI's clinical trials website.
When you or someone you love is diagnosed with cancer, concerns about treatments and managing side effects, hospital stays, and medical bills are common. You may also worry about caring for your family, employment, or how to continue normal daily activities.
Here's where you can go for support:
- Your health care team can answer your questions and talk to you about your concerns. They can help you with any side effects and keep you informed of all your treatments, test results, and future doctor visits.
- Our Patient and Family Support Services professionals offer HCI patients and their families emotional support and resources for coping with cancer and its impact on daily life.
- The Linda B. and Robert B. Wiggins Wellness-Survivorship Center offers support groups, classes, and activities aimed to increase the quality of life and well-being of HCI patients and their families.
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Head and Neck Cancer Program
Care coordinator: Keri Carter
Did You Know?
- Thyroid cancer accounts for about 1.6% of all cancers diagnosed in the United States.
- In the United States, women are almost three times more likely than men to develop thyroid cancer.
- Scientists are studying iodine as a possible risk factor for thyroid cancer. Too little iodine in the diet may increase the risk of follicular thyroid cancer; however, other studies show that too much iodine in the diet may increase the risk of papillary thyroid cancer. More studies are needed to know whether iodine is a risk factor.