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.

Thyroid nodules are common but usually are not cancer.

Your doctor may find a lump (nodule) in your thyroid during a routine medical exam. A thyroid nodule is an abnormal growth of thyroid cells in the thyroid. Nodules may be solid or fluid-filled.

When a thyroid nodule is found, an ultrasound of the thyroid and a fine-needle aspiration biopsy are often done to check for signs of cancer. Blood tests to check thyroid hormone levels and for antithyroid antibodies in the blood may also be done to check for other types of thyroid disease.

Thyroid nodules usually don't cause symptoms or need treatment. Sometimes the thyroid nodules become large enough that it is hard to swallow or breathe and more tests and treatment are needed. Only a small number of thyroid nodules are diagnosed as cancer.

There are different types of thyroid cancer.

Thyroid cancer can be described as either:

• Differentiated thyroid cancer, which includes well-differentiated tumors, poorly differentiated tumors, and undifferentiated tumors; or
• Medullary thyroid cancer.

Well-differentiated tumors (papillary thyroid cancer and follicular thyroid cancer) can be treated and can usually be cured.

Poorly differentiated and undifferentiated tumors (anaplastic thyroid cancer) are less common. These tumors grow and spread quickly and have a poorer chance of recovery. Patients with anaplastic thyroid cancer should have molecular testing for a mutation in the BRAF gene.

Medullary thyroid cancer is a neuroendocrine tumor that develops in C cells of the thyroid. The C cells make a hormone (calcitonin) that helps maintain a healthy level of calcium in the blood.

What is thyroid cancer?

Thyroid cancer is a cancer that starts in the tissues of the thyroid. Your thyroid is a small, butterfly-shaped gland in the front of your neck. It makes hormones that control the way the body uses energy. These hormones affect nearly every organ in your body and control many of your body's most important functions. For example, they affect your breathing, heart rate, weight, digestion, and moods.

What are the different types of thyroid cancer?

There are different types of thyroid cancer; the main ones include:

• Differentiated thyroid cancer, which includes papillary cancer and follicular cancer
• Medullary thyroid cancer
• Anaplastic thyroid cancer

Who is more likely to develop thyroid cancer?

Certain people are more likely to develop thyroid cancer. Your risk is higher if you:

• Are between ages 25 and 65
• Are a woman
• Are Asian
• Were exposed to certain types of radiation, including from radiation treatments to your head or neck as a child or from a radiation emergency
• Have had a goiter (enlarged thyroid)
• Having certain genetic conditions, including certain types of multiple endocrine neoplasia
• Have a family history of thyroid cancer or thyroid disease

What are the symptoms of thyroid cancer?

Thyroid cancer may not cause symptoms at first. It is sometimes found during a routine physical exam. You may get signs or symptoms as the cancer gets bigger. The symptoms may include:

• A lump (nodule) in the neck
• Trouble breathing
• Trouble swallowing
• Pain when swallowing
• Hoarseness or other changes to your voice that do not get better

How is thyroid cancer diagnosed?

To find out if you have thyroid cancer, your health care provider may use:

• A physical exam, including checking your neck for swelling, lumps, or anything that seems unusual
• A medical history
• Thyroid tests
• Other blood or imaging tests
• A biopsy

What are the treatments for thyroid cancer?

Treatment for thyroid cancer depends on the type of cancer you have and whether the cancer has spread. Often, more than one type of treatment may be needed. The treatment options include:

• Surgery.
• Radiation therapy, including radioactive iodine therapy.
• Chemotherapy.
• Thyroid hormone therapy.
• Targeted therapy, which uses drugs or other substances that attack specific cancer cells with less harm to normal cells.
• Watchful waiting, which means that you don't get treatment right away. Your regularly checks to see if your signs or symptoms appear or change.

A butterfly-shaped organ, the thyroid gland is located anterior to the trachea, just inferior to the larynx. The medial region, called the isthmus, is flanked by wing-shaped left and right lobes. Each of the thyroid lobes are embedded with parathyroid glands, primarily on their posterior surfaces. The tissue of the thyroid gland is composed mostly of thyroid follicles. The follicles are made up of a central cavity filled with a sticky fluid called colloid . Surrounded by a wall of epithelial follicle cells, the colloid is the center of thyroid hormone production, and that production is dependent on the hormones’ essential and unique component: iodine.

Review

The thyroid gland is a butterfly-shaped organ located in the neck anterior to the trachea. Its hormones regulate basal metabolism, oxygen use, nutrient metabolism, the production of ATP, and calcium homeostasis. They also contribute to protein synthesis and the normal growth and development of body tissues, including maturation of the nervous system, and they increase the body’s sensitivity to catecholamines. The thyroid hormones triiodothyronine (T₃) and thyroxine (T₄) are produced and secreted by the thyroid gland in response to thyroid-stimulating hormone (TSH) from the anterior pituitary. Synthesis of the amino acid–derived T₃ and T₄ hormones requires iodine. Insufficient amounts of iodine in the diet can lead to goiter, cretinism, and many other disorders.

The parathyroid glands are tiny, round structures usually found embedded in the posterior surface of the thyroid gland (image). A thick connective tissue capsule separates the glands from the thyroid tissue. Most people have four parathyroid glands, but occasionally there are more in tissues of the neck or chest. The function of one type of parathyroid cells, the oxyphil cells, is not clear. The primary functional cells of the parathyroid glands are the chief cells. These epithelial cells produce and secrete the parathyroid hormone (PTH) , the major hormone involved in the regulation of blood calcium levels.

The parathyroid glands produce and secrete PTH, a peptide hormone, in response to low blood calcium levels (image). PTH secretion causes the release of calcium from the bones by stimulating osteoclasts, which secrete enzymes that degrade bone and release calcium into the interstitial fluid. PTH also inhibits osteoblasts, the cells involved in bone deposition, thereby sparing blood calcium. PTH causes increased reabsorption of calcium (and magnesium) in the kidney tubules from the urine filtrate. In addition, PTH initiates the production of the steroid hormone calcitriol (also known as 1,25-dihydroxyvitamin D), which is the active form of vitamin D₃, in the kidneys. Calcitriol then stimulates increased absorption of dietary calcium by the intestines. A negative feedback loop regulates the levels of PTH, with rising blood calcium levels inhibiting further release of PTH.

Abnormally high activity of the parathyroid gland can cause hyperparathyroidism , a disorder caused by an overproduction of PTH that results in excessive calcium reabsorption from bone. Hyperparathyroidism can significantly decrease bone density, leading to spontaneous fractures or deformities. As blood calcium levels rise, cell membrane permeability to sodium is decreased, and the responsiveness of the nervous system is reduced. At the same time, calcium deposits may collect in the body’s tissues and organs, impairing their functioning.

In contrast, abnormally low blood calcium levels may be caused by parathyroid hormone deficiency, called hypoparathyroidism , which may develop following injury or surgery involving the thyroid gland. Low blood calcium increases membrane permeability to sodium, resulting in muscle twitching, cramping, spasms, or convulsions. Severe deficits can paralyze muscles, including those involved in breathing, and can be fatal.

When blood calcium levels are high, calcitonin is produced and secreted by the parafollicular cells of the thyroid gland. As discussed earlier, calcitonin inhibits the activity of osteoclasts, reduces the absorption of dietary calcium in the intestine, and signals the kidneys to reabsorb less calcium, resulting in larger amounts of calcium excreted in the urine.

Overview

Calcium is required for a variety of important physiologic processes, including neuromuscular functioning; thus, blood calcium levels are closely regulated. The parathyroid glands are small structures located on the posterior thyroid gland that produce parathyroid hormone (PTH), which regulates blood calcium levels. Low blood calcium levels cause the production and secretion of PTH. In contrast, elevated blood calcium levels inhibit secretion of PTH and trigger secretion of the thyroid hormone calcitonin. Underproduction of PTH can result in hypoparathyroidism. In contrast, overproduction of PTH can result in hyperparathyroidism.

Age, gender, and being exposed to radiation can affect the risk of 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. Talk with your doctor if you think you may be at risk.

Risk factors for thyroid cancer include the following:

• Being between 25 and 65 years old.
• Being female.
• Being exposed to radiation to the head and neck as an infant or child or being exposed to radioactive fallout. The cancer may occur as soon as 5 years after exposure.
• Having a history of goiter (enlarged thyroid).
• Having a family history of thyroid disease or thyroid cancer.
• Having certain genetic conditions such as familial medullary thyroid cancer (FMTC), multiple endocrine neoplasia type 2A syndrome (MEN2A), or multiple endocrine neoplasia type 2B syndrome (MEN2B).
• Being Asian.

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 the RET gene that is passed from parent to child (inherited) may cause medullary thyroid cancer.

There is a genetic test that is used to check for the changed gene. 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 to find out if they are at increased risk for medullary thyroid cancer. Family members, including young children, who have the changed gene may have a thyroidectomy (surgery to remove the thyroid). This can decrease the chance of developing medullary thyroid cancer.

Signs of thyroid cancer include a swelling or lump in the neck.

Thyroid cancer may not cause early signs or symptoms. It is sometimes found during a routine physical exam. Signs or symptoms may occur as the tumor gets bigger. Other conditions may cause the same signs or symptoms. Check with your doctor if you have any of the following:

• A lump (nodule) in the neck.
• Trouble breathing.
• Trouble swallowing.
• Pain when swallowing.
• Hoarseness.

Tests that examine the thyroid, neck, and blood are used to diagnose thyroid cancer.

The following tests and procedures may be used:

• Physical exam and health history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps (nodules) 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 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 and antithyroid antibodies.
• 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.
• Ultrasound exam: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs in the neck 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 nodule 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, such as the neck, 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.

• 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.

KEY POINTS

• 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.
• There are three ways that cancer spreads in the body.
• Cancer may spread from where it began to other parts of the body.
• Stages are used to describe thyroid cancer based on the type of thyroid cancer and the age of the patient:
  • Papillary and follicular thyroid cancer in patients younger than 55 years
  • Papillary and follicular thyroid cancer in patients 55 years and older
  • Anaplastic thyroid cancer in patients of all ages
  • Medullary thyroid cancer in patients of all ages
• Thyroid cancer can recur (come back) after it has been treated.

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 patient's age and the stage of the cancer 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, such as the chest, abdomen, and brain, 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.
• 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.
• 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.
• 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 with cancer and is detected by a scanner.
• Sentinel lymph node biopsy: The removal of the sentinel lymph node during surgery. The sentinel lymph node is the first lymph node in a group of lymph nodes to receive lymphatic drainage from the primary tumor. It is the first lymph node the cancer is likely to spread to from the primary tumor. A radioactive substance and/or blue dye is injected near the tumor. The substance or dye flows through the lymph ducts to the lymph nodes. The first lymph node to receive the substance or dye is removed. A pathologist views the tissue under a microscope to look for cancer cells. If cancer cells are not found, it may not be necessary to remove more lymph nodes.

There are three ways that cancer spreads in the body.

Cancer can spread through tissue, the lymph system, and the blood:

• Tissue. The cancer spreads from where it began by growing into nearby areas.
• Lymph system. The cancer spreads from where it began by getting into the lymph system. The cancer travels through the lymph vessels to other parts of the body.
• Blood. The cancer spreads from where it began by getting into the blood. The cancer travels through the blood vessels to other parts of the body.

Cancer may spread from where it began to other parts of the body.

When cancer spreads to another part of the body, it is called metastasis. Cancer cells break away from where they began (the primary tumor) and travel through the lymph system or blood.

• Lymph system. The cancer gets into the lymph system, travels through the lymph vessels, and forms a tumor (metastatic tumor) in another part of the body.
• Blood. The cancer gets into the blood, travels through the blood vessels, and forms a tumor (metastatic tumor) in another part of the body.

The metastatic tumor is the same type of cancer as the primary tumor. For example, if thyroid cancer spreads to the lung, the cancer cells in the lung are actually thyroid cancer cells. The disease is metastatic thyroid cancer, not lung cancer.

Stages are used to describe thyroid cancer based on the type of thyroid cancer and the age of the patient:

Papillary and follicular thyroid cancer in patients younger than 55 years

• Stage I: In stage I papillary and follicular thyroid cancer, the tumor is any size and 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, the tumor is any size and cancer may have spread to nearby tissues and lymph nodes. Cancer has spread from the thyroid to other parts of the body, such as the lungs or bones.

Papillary and follicular thyroid cancer in patients 55 years and older

• Stage I: In stage I papillary and follicular thyroid cancer, cancer is found in the thyroid only and the tumor is 4 centimeters or smaller.

• Stage II: In stage II papillary and follicular thyroid cancer, one of the following is found:
  • cancer is found in the thyroid and the tumor is 4 centimeters or smaller; cancer has spread to nearby lymph nodes; or
  • cancer is found in the thyroid, the tumor is larger than 4 centimeters, and cancer may have spread to nearby lymph nodes; or
  • the tumor is any size and cancer has spread from the thyroid to nearby muscles in the neck and may have spread to nearby lymph nodes.

• Stage III: In stage III papillary and follicular thyroid cancer, the tumor is any size and cancer has spread from the thyroid to soft tissue under the skin, the esophagus, the trachea, the larynx, or the recurrent laryngeal nerve (a nerve that goes to the larynx). Cancer may have spread to lymph nodes.

• Stage IV: Stage IV papillary and follicular thyroid cancer is divided into stages IVA and IVB.
  • In stage IVA, the tumor is any size and cancer has spread to tissue in front of the spine or has surrounded the carotid artery or the blood vessels in the area between the lungs. Cancer may have spread to lymph nodes.

  • In stage IVB, the tumor is any size and cancer has spread to other parts of the body, such as the lungs or bones. Cancer may have spread to lymph nodes.

Anaplastic thyroid cancer in patients of all ages

Anaplastic thyroid cancer grows quickly and usually has spread within the neck when it is found. Anaplastic thyroid cancer is considered stage IV thyroid cancer. Stage IV anaplastic thyroid cancer is divided into stages IVA, IVB, and IVC.

• In stage IVA, cancer is found in the thyroid only and the tumor may be any size.

• In stage IVB, one of the following is found:
  • cancer is found in the thyroid and the tumor may be any size; cancer has spread to nearby lymph nodes; or

  • the tumor is any size and cancer has spread from the thyroid to nearby muscles in the neck and may have spread to nearby lymph nodes; or

  • the tumor is any size and cancer has spread from the thyroid to soft tissue under the skin, the esophagus, the trachea, the larynx, the recurrent laryngeal nerve (a nerve that goes to the larynx), or tissue in front of the spine, or has surrounded the carotid artery or the blood vessels in the area between the lungs; cancer may have spread to lymph nodes.

• In stage IVC, the tumor is any size and cancer has spread to other parts of the body, such as the lungs or bones. Cancer may have spread to lymph nodes.

Medullary thyroid cancer in patients of all ages

• Stage I: In stage I medullary thyroid cancer, cancer is found in the thyroid only and the tumor is 2 centimeters or smaller.

• Stage II: In stage II medullary thyroid cancer, one of the following is found:
  • cancer is in the thyroid only and the tumor is larger than 2 centimeters; or
  • the tumor is any size and cancer has spread from the thyroid to nearby muscles in the neck.

• Stage III: In stage III medullary thyroid cancer, the tumor is any size and cancer may have spread from the thyroid to nearby muscles in the neck. Cancer has spread to lymph nodes on one or both sides of the trachea or larynx.

• Stage IV: Stage IV medullary thyroid cancer is divided into stages IVA, IVB, and IVC.
  • In stage IVA, either of the following is found:
    • the tumor is any size and cancer has spread from the thyroid to soft tissue under the skin, the esophagus, the trachea, the larynx, or the recurrent laryngeal nerve (a nerve that goes to the larynx); cancer may have spread to lymph nodes on one or both sides of the neck; or
    • the tumor is any size and cancer may have spread from the thyroid to nearby muscles in the neck; cancer has spread to lymph nodes on one or both sides of the neck.

• In stage IVB, the tumor is any size and cancer has spread to tissue in front of the spine or to the spine or has surrounded the carotid artery or the blood vessels in the area between the lungs. Cancer may have spread to lymph nodes.

• In stage IVC, the tumor is any size and cancer has spread to other parts of the body, such as the lungs or liver. Cancer may have spread to lymph nodes.

Thyroid cancer can recur (come back) after it has been treated.

The cancer may come back in the thyroid or in other parts of the body.

Treatment Option Overview

KEY POINTS

• There are different types of treatment for patients with thyroid cancer.
• The following types of treatment are used:
  • Surgery
  • Radiation therapy, including radioactive iodine therapy
  • Chemotherapy
  • Thyroid hormone therapy
  • Targeted therapy
  • Watchful waiting
• New types of treatment are being tested in clinical trials.
  • Immunotherapy
• Treatment for thyroid cancer may cause side effects.
• Patients may want to think about taking part in a clinical trial.
• Patients can enter clinical trials before, during, or after starting their cancer treatment.
• Follow-up tests may be needed.

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.

The following types of treatment are used:

Surgery

Surgery is the most common treatment for thyroid cancer. One of the following procedures may be used:

• Lobectomy: Removal of the lobe in which thyroid cancer is found. Lymph nodes near the cancer may also be removed and checked under a microscope for signs of cancer.
• Near-total thyroidectomy: Removal of all but a very small part of the thyroid. Lymph nodes near the cancer may also be removed and checked under a microscope for signs of cancer.
• Total thyroidectomy: Removal of the whole thyroid. Lymph nodes near the cancer may also be removed and checked under a microscope for signs of cancer.
• Tracheostomy: Surgery to create an opening (stoma) into the windpipe to help you breathe. The opening itself may also be called a tracheostomy.

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 area of the body with cancer. Sometimes the radiation is aimed directly at the tumor during surgery. This is called intraoperative radiation therapy.
• Internal radiation therapy uses a radioactive substance sealed in needles, seeds, wires, or catheters that are placed directly into or near the cancer.

Radiation therapy may be given after surgery to kill any thyroid cancer cells that were not removed. Follicular and papillary thyroid cancers are sometimes treated with radioactive iodine (RAI) therapy. RAI is taken by mouth and collects in any remaining thyroid tissue, including thyroid cancer cells that have spread to other places in the body. Since only thyroid tissue takes up iodine, the RAI destroys thyroid tissue and thyroid cancer cells without harming other tissue. Before a full treatment dose of RAI is given, a small test-dose is given to see if the tumor takes up the iodine.

The way the radiation therapy is given depends on the type and stage of the cancer being treated. External radiation therapy and radioactive iodine (RAI) therapy are used to treat thyroid cancer.

Chemotherapy

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). When chemotherapy is placed directly into the cerebrospinal fluid, an organ, or a body cavity such as the abdomen, the drugs mainly affect cancer cells in those areas (regional chemotherapy).

The way the chemotherapy is given depends on the type and stage of the cancer being treated.

Thyroid hormone therapy

Hormone therapy is a cancer treatment that removes hormones or blocks their action and stops cancer cells from growing. Hormones are substances made by glands in the body and circulated in the bloodstream. In the treatment of thyroid cancer, drugs may be given to prevent the body from making thyroid-stimulating hormone (TSH), a hormone that can increase the chance that thyroid cancer will grow or recur.

Also, because thyroid cancer treatment kills thyroid cells, the thyroid is not able to make enough thyroid hormone. Patients are given thyroid hormone replacement pills.

Targeted therapy

Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells. There are different types of targeted therapy:

• Tyrosine kinase inhibitor. Tyrosine kinase inhibitor therapy blocks signals needed for tumors to grow. Sorafenib, lenvatinib, vandetanib, cabozantinib, selpercatinib, larotrectinib, entrectinib, and pralsetinib are used to treat certain types of thyroid cancer. New types of tyrosine kinase inhibitors are being studied to treat advanced thyroid cancer.
• Protein kinase inhibitor. Protein kinase inhibitor therapy blocks proteins needed for cell growth and may kill cancer cells. Dabrafenib and trametinib are used to treat anaplastic thyroid cancer in patients with a certain mutation in the BRAF gene.

Watchful waiting

Watchful waiting is closely monitoring a patient’s condition without giving any treatment until signs or symptoms appear or change.

Immunotherapy

Immunotherapy is a treatment that uses the patient’s immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body’s natural defenses against cancer. This cancer treatment is a type of biologic therapy. Immunotherapy is being studied as a treatment for thyroid cancer.

Treatment for thyroid cancer may cause side effects.

Patients may want to think about taking part in a clinical trial.

For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and effective or better than the standard treatment.

Many of today's standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.

Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and help move research forward.

Patients can enter clinical trials before, during, or after starting their cancer treatment.

Some clinical trials only include patients who have not yet received treatment. Other trials test treatments for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.

Clinical trials are taking place in many parts of the country. Information about clinical trials supported by NCI can be found on NCI’s clinical trials search webpage. Clinical trials supported by other organizations can be found on the ClinicalTrials.gov website.

Follow-up tests may be needed.

Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests.

Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back). These tests are sometimes called follow-up tests or check-ups.

Treatment of stage I (younger than 55 years; 55 years and older), stage II (younger than 55 years; 55 years and older), and stage III papillary and follicular thyroid cancer may include the following:

• Surgery (thyroidectomy or lobectomy).
• Radioactive iodine therapy.
• Hormone therapy to prevent the body from making thyroid-stimulating hormone (TSH).
• External radiation therapy.

When cancer has spread to other places in the body, such as the lungs and bone, treatment usually does not cure the cancer, but can relieve symptoms and improve the quality of life. Treatment of stage IV papillary and follicular thyroid cancer may include the following:

For tumors that take up iodine

• Total thyroidectomy.
• Radioactive iodine therapy.
• Hormone therapy to prevent the body from making thyroid-stimulating hormone (TSH).

For tumors that do not take up iodine

• Total thyroidectomy.
• Hormone therapy to prevent the body from making thyroid-stimulating hormone (TSH).
• Targeted therapy with a tyrosine kinase inhibitor (sorafenib or lenvatinib).
• Surgery to remove cancer from areas where it has spread.
• External-beam radiation therapy.
• A clinical trial of chemotherapy.
• A clinical trial of a targeted therapy.
• A clinical trial of immunotherapy.

Treatment of recurrent papillary and follicular thyroid cancer may include the following:

• Surgery to remove the tumor with or without radioactive iodine therapy.
• Radioactive iodine therapy when the cancer can be found only by a thyroid scan and cannot be felt during a physical exam.
• Targeted therapy with a tyrosine kinase inhibitor (sorafenib, lenvatinib, cabozantinib, selpercatinib, pralsetinib, larotrectinib, or entrectinib).
• External radiation therapy or intraoperative radiation therapy as palliative therapy to relieve symptoms and improve the quality of life.
• Chemotherapy.
• A clinical trial of a targeted therapy.
• A clinical trial of immunotherapy.

Localized medullary thyroid cancer is in the thyroid only and may have spread to nearby muscles in the neck. Locally advanced and metastatic thyroid cancer has spread to other parts of the neck or to other parts of the body.

Treatment of localized medullary thyroid cancer may include the following:

• Total thyroidectomy if the cancer has not spread to other parts of the body. Lymph nodes near the cancer are also removed.
• External radiation therapy for patients whose cancer has recurred in the thyroid.

Treatment of locally advanced/metastatic medullary thyroid cancer may include the following:

• Targeted therapy with a tyrosine kinase inhibitor (vandetanib, cabozantinib, selpercatinib, or pralsetinib) for cancer that has spread to other parts of the body.
• Chemotherapy as palliative therapy to relieve symptoms and improve the quality of life for patients whose cancer has spread to other parts of the body.

Radioactive iodine therapy is not used to treat medullary thyroid cancer.

Treatment of anaplastic thyroid cancer may include the following:

• Total thyroidectomy as palliative therapy to relieve symptoms and improve the quality of life for patients whose cancer is in or near the thyroid.
• Tracheostomy as palliative therapy to relieve symptoms and improve the quality of life.
• External radiation therapy.
• Chemotherapy.
• Targeted therapy with protein kinase inhibitors (dabrafenib and trametinib) for patients with a certain mutation in the BRAF gene.

This page lists cancer drugs approved by the Food and Drug Administration (FDA) for thyroid cancer. The list includes generic names and brand names. The drug names link to NCI's Cancer Drug Information summaries. There may be drugs used in thyroid cancer that are not listed here.

Drugs Approved for Thyroid Cancer

• Cabozantinib-S-Malate
• Caprelsa (Vandetanib)
• Cometriq (Cabozantinib-S-Malate)
• Dabrafenib Mesylate
• Doxorubicin Hydrochloride
• Gavreto (Pralsetinib)
• Lenvatinib Mesylate
• Lenvima (Lenvatinib Mesylate)
• Mekinist (Trametinib Dimethyl Sulfoxide)
• Nexavar (Sorafenib Tosylate)
• Pralsetinib
• Retevmo (Selpercatinib)
• Selpercatinib
• Sorafenib Tosylate
• Tafinlar (Dabrafenib Mesylate)
• Trametinib Dimethyl Sulfoxide
• Vandetanib

Cancer treatments and cancer can cause side effects. Side effects are problems that occur when treatment affects healthy tissues or organs. Speak up about any problems you have. Your health care team can treat and/or talk with you about ways to reduce these side effects, so you feel better.

Learn about steps you can take to prevent or manage the side effects listed below:

• Anemia
• Appetite Loss
• Bleeding and Bruising (Thrombocytopenia)
• Constipation
• Delirium
• Diarrhea
• Edema (Swelling)
• Fatigue
• Fertility Issues in Boys and Men
• Fertility Issues in Girls and Women
• Flu-Like Symptoms
• Hair Loss (Alopecia)
• Infection and Neutropenia
• Lymphedema
• Memory or Concentration Problems
• Mouth and Throat Problems
• Nausea and Vomiting
• Nerve Problems (Peripheral Neuropathy)
• Immunotherapy and Organ-Related Inflammation
• Pain
• Sexual Health Issues in Men
• Sexual Health Issues in Women
• Skin and Nail Changes
• Sleep Problems
• Urinary and Bladder Problems

Keep in mind that side effects vary from person to person, even among people receiving the same type of cancer treatment.

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis and treatment options depend on the following:

• The age of the patient at the time of diagnosis.
• The type of thyroid cancer.
• The stage of the cancer.
• Whether the cancer was completely removed by surgery.
• Whether the patient has multiple endocrine neoplasia type 2B (MEN 2B).
• The patient's general health.
• Whether the cancer has just been diagnosed or has recurred (come back).