General Information About Childhood Thyroid Cancer

KEY POINTS

• Thyroid cancer is a disease in which malignant (cancer) cells form in the tissues of the thyroid gland.
• Thyroid nodules may be adenomas or carcinomas.
• Thyroid nodules may be found during a routine medical exam and are usually not cancer.
• Being exposed to radiation or having certain genetic syndromes can affect the risk of thyroid cancer.
• Medullary thyroid cancer is sometimes caused by a change in a gene that is passed from parent to child.
• Signs of thyroid cancer include a swelling or lump in the neck.
• Tests that examine the thyroid, neck, and blood are used to detect (find), diagnose, and stage thyroid cancer.
• Certain factors affect prognosis (chance of recovery).

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 is a thin piece of tissue that connects the two lobes. 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 may be adenomas or carcinomas.

There are two types of thyroid nodules:

• Adenomas: Adenomas can grow very large and sometimes make hormones. Adenomas are not cancer but may rarely become malignant (cancer) and spread to the lungs or lymph nodes in the neck.
• Carcinomas: There are three main types of thyroid carcinoma in children:
  • Papillary. Papillary thyroid carcinoma is the most common type of thyroid cancer in children. It occurs most often in teens. Papillary thyroid carcinoma is often made up of more than one nodule on both sides of the thyroid. It often spreads to the lymph nodes in the neck and may also spread to the lung. The prognosis (chance of recovery) for most patients is very good.
  • Follicular. Follicular thyroid carcinoma is usually made up of one nodule. It often spreads to the bone and lung, but rarely spreads to the lymph nodes in the neck. The prognosis for most patients is very good.
  • Medullary. Medullary thyroid carcinoma forms from parafollicular C cells in the thyroid. It is usually linked to a certain inherited change in the RET gene and multiple endocrine neoplasia type 2 (MEN 2) syndrome. It occurs most often in children aged 4 years and younger and may have spread to other parts of the body at the time of diagnosis. Children who have MEN2 syndrome may also be at risk of developing pheochromocytoma or hyperparathyroidism.

Papillary and follicular thyroid cancer are sometimes called differentiated thyroid cancer. Medullary and anaplastic thyroid cancer are sometimes called poorly differentiated or undifferentiated thyroid cancer. Anaplastic thyroid cancer is very rare in children and is not discussed in this summary.

Thyroid nodules may be found during a routine medical exam and are usually not cancer.

Your child’s doctor may find a lump (nodule) in the thyroid during a routine medical exam, or a nodule may be seen on an imaging test or during surgery for another condition. 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 lymph nodes in the neck is done. A fine-needle aspiration biopsy may be done to check for signs of cancer. Blood tests to check thyroid hormone levels and for anti-thyroid antibodies in the blood may also be done. This is 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 one in five thyroid nodules become 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 your child may be at risk.

Risk factors for childhood thyroid cancer include the following:

• Being exposed to radiation, such as from diagnostic tests, radiation treatment, or radiation in the environment.
• Having a family history of thyroid cancer, including the following:
  • APC-associated polyposis.
  • DICER1 syndrome.
  • Carney complex.
  • PTEN hamartoma tumor syndrome.
  • Werner syndrome.
• Having certain genetic syndromes, such as the following:
  • Multiple endocrine neoplasia type 2A (MEN2A) syndrome.
  • Multiple endocrine neoplasia type 2B (MEN2B) syndrome.

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 have an increased risk of 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.

Sometimes thyroid tumors do not cause any signs or symptoms. These and other signs and symptoms may be caused by papillary or follicular thyroid cancer or by other conditions.

Check with your child's doctor if your child has any of the following:

• A lump in the neck.
• Trouble breathing.
• Trouble swallowing.
• Hoarseness or a change in the voice.

These and other signs and symptoms may be caused by medullary thyroid cancer or by other conditions.

Check with your child's doctor if your child has any of the following:

• Bumps on the lips, tongue, or eyelids that do not hurt.
• Trouble making tears.
• Constipation.
• Marfan syndrome (being tall and thin, with long arms, legs, fingers, and toes).

Tests are done to detect, diagnose, and stage cancer. After cancer is diagnosed, more tests are done to find out if cancer cells have spread to nearby areas or to other parts of the body. This process is called staging. Tests done to find out if cancer cells have spread before the tumor is removed by surgery is called preoperative staging. It is important to know whether cancer has spread in order to plan the best treatment.

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.
• Thyroid function test: The blood is 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 calcitonin (a hormone made by the thyroid that decreases the amount of calcium in the blood).
• Thyroglobulin test: The blood is checked for the amount of thyroglobulin, a protein made by the thyroid gland. Thyroglobulin levels are low or absent with normal thyroid function but may be higher with thyroid cancer or other conditions.
• RET gene test: A laboratory test in which a sample of blood or tissue is tested for certain changes in the RET gene. This test is done for children who may have medullary thyroid cancer.
• 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. A complete ultrasound exam of the neck is done before surgery.
• Thyroid scan: A small amount of a radioactive substance is swallowed or injected. The radioactive material collects in thyroid gland cells. A special camera linked to a computer detects the radiation given off and makes pictures that show how the thyroid looks and functions and whether the cancer has spread beyond the thyroid gland. If the amount of TSH in the child's blood is low, a scan to make images of the thyroid may be done before surgery.
• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the neck, 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.

• MRI (magnetic resonance imaging) with gadolinium: A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body, such as the neck and chest. A substance called gadolinium is injected into a vein. The gadolinium collects around the cancer cells so they show up brighter in the picture. This procedure is also called nuclear magnetic resonance imaging (NMRI).
• 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.
• Fine-needle aspiration biopsy: 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. If it is not clear whether cancer is present, a surgicalbiopsy may be done.
• 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).

The prognosis (chance of recovery) depends on the following:

• The age of the child at the time of diagnosis.
• The type of thyroid cancer.
• The size of the cancer.
• Whether the tumor has spread to lymph nodes or other parts of the body at the time of diagnosis.
• Whether the cancer was completely removed by surgery.
• The child's general health.

KEY POINTS

• After the cancer has been removed by surgery, tests are done to find out if cancer cells remain in 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.

After the cancer has been removed by surgery, tests are done to find out if cancer cells remain in the body.

Tests are done after surgery to find out if cancer cells remain and to determine if more treatment is needed. This is called postoperative staging.

The following tests and procedures may be done about 12 weeks after surgery:

• 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 thyroidnodule and whether it is solid or a fluid-filled cyst. Ultrasound may be used to guide a fine-needle aspiration biopsy. A complete ultrasound exam of the neck is done before surgery.
• Thyroglobulin test: A test that measures the amount of thyroglobulin in the blood. Thyroglobulin is a protein made by the thyroid gland. Thyroglobulin levels are low or absent with normal thyroid function but may be higher with thyroid cancer or other conditions.
• Whole-body thyroid scan: A small amount of radioactive substance is swallowed or injected. The radioactive material collects in any thyroid tissue or cancer cells remaining after surgery. Radioactive iodineis used because only thyroid cells take up iodine. A special camera detects the radiation given off by the thyroid tissue or cancer cells, also called radioactive iodine scan or RAI scan.

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.

Recurrent Childhood 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.

Treatment Option Overview

KEY POINTS

• There are different types of treatment for patients with thyroid cancer.
• Children with thyroid cancer should have their treatment planned by a team of doctors who are experts in treating childhood cancer.
• Four types of standard treatment are used:
  • Surgery
  • Radioactive iodine therapy
  • Targeted therapy
  • Hormone replacement therapy
• New types of treatment are being tested in clinical trials.
• Treatment for childhood 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.

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.

Because cancer in children is rare, taking part in a clinical trial should be considered. Some clinical trials are open only to patients who have not started treatment.

Children with thyroid cancer should have their treatment planned by a team of doctors who are experts in treating childhood cancer.

Treatment will be overseen by a pediatric oncologist, a doctor who specializes in treating children with cancer. The pediatric oncologist works with other pediatric health professionals who are experts in treating children with cancer and who specialize in certain areas of medicine. This may include the following specialists and others:

• Pediatrician.
• Pediatric surgeon.
• Radiation oncologist.
• Pathologist.
• Pediatric nurse specialist.
• Social worker.
• Rehabilitation specialist.
• Psychologist.
• Child-life specialist.

Four types of standard treatment are used:

Surgery

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

• 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.
• 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.

In children, a total thyroidectomy is usually done.

Radioactive iodine therapy

Follicular and papillary thyroid cancers are sometimes treated with radioactive iodine (RAI) therapy. RAI therapy may be given to children after surgery to kill any thyroid cancer cells that were not removed or to children whose tumor cannot be removed by surgery. 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. Because 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.

Targeted therapy

Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells while causing less harm to normal cells.

Tyrosine kinase inhibitor therapy (TKI) is a type of targeted therapy that blocks signals needed for tumors to grow. Vandetanib is a TKI used to treat children with advanced medullary thyroid cancer.

Targeted therapy is being studied for the treatment of childhood thyroid cancer that has recurred (come back).

Hormone replacement therapy

Hormones are substances made by glands in the body and circulated in the bloodstream. After treatment for thyroid cancer, the thyroid is not able to make enough thyroid hormone. Patients are given thyroid hormone replacement pills for the rest of their lives.

New types of treatment are being tested in clinical trials.

Information about clinical trials is available from the NCI website.

Treatment for childhood thyroid cancer may cause side effects.

For information about side effects that begin during treatment for cancer, see our Side Effects page.

Side effects from cancer treatment that begin after treatment and continue for months or years are called late effects. Late effects of cancer treatment for childhood thyroid cancer may include:

• Physical problems, such as changes in the salivary glands, infection, or trouble breathing.
• Changes in mood, feelings, thinking, learning, or memory.
• Second cancers (new types of cancer).

Some late effects may be treated or controlled. It is important to talk with your child's doctors about the effects cancer treatment can have on your child.

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.

Follow-up tests may be needed.

It is common for thyroid cancer to recur (come back), especially in children younger than 10 years and those with cancer in the lymph nodes. Ultrasound, whole-body scan, and thyroglobulin tests may be done from time to time to check if the cancer has recurred. Lifelong follow-up of thyroid hormone levels in the blood is needed to make sure the right amount of hormone replacement therapy (HRT) is being given. Talk with your child's doctor to find out how often these tests need to be done.

Treatment of Childhood Papillary and Follicular Thyroid Cancer

For information about the treatments listed below, see the Treatment Option Overview section.

Treatment of papillary and follicular thyroid carcinoma in children may include the following:

• Surgery to remove all or most of the thyroid gland and sometimes lymph nodes near the thyroid gland. Radioactive iodine therapy may also be given if any thyroid cancer cells remain after surgery. Hormone replacement therapy (HRT) is given to make up for the lost thyroid hormone.

Within 12 weeks of surgery, tests are done to find out if thyroid cancer remains in the body. These may include thyroglobulin tests and a whole-body thyroid scan. A whole-body thyroid scan is done to find areas in the body where thyroid cancer cells that were not removed during surgery may be dividing quickly. Radioactive iodine is used because only thyroid cells take up iodine. A very small amount of radioactive iodine is swallowed, travels through the blood, and collects in thyroid tissue and thyroid cancer cells anywhere in the body. If thyroid cancer remains, a large dose of radioactive iodine is given to destroy any remaining thyroid cancer cells. A whole-body SPECT (single photon emission computed tomography) scanmay be done 4 to 7 days after treatment to check whether all of the cancer cells have been destroyed.

• Radioactive iodine therapy alone may be given to children whose tumor cannot be removed by surgery. Hormone replacement therapy (HRT) is given to make up for the lost thyroid hormone.

See the Multiple Endocrine Neoplasia Syndromes section of the PDQ summary on Unusual Cancers of Childhood Treatment for more information.

Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done.

Treatment of Childhood Medullary Thyroid Cancer

For information about the treatments listed below, see the Treatment Option Overview section.

Treatment of medullary thyroid carcinoma in children may include the following:

• Surgery to remove the cancer.
• Targeted therapy with a tyrosine kinase inhibitor (vandetanib) for cancer that is advanced or has spread to other parts of the body.

Use our clinical trial search to find NCI-supported cancer clinical trials that are accepting patients. You can search for trials based on the type of cancer, the age of the patient, and where the trials are being done.

Treatment of Progressive or Recurrent Childhood Thyroid Cancer

For information about the treatments listed below, see the Treatment Option Overview section.

Treatment of progressive or recurrent papillary and follicular thyroid carcinoma in children may include the following:

• Radioactive iodine (RAI) therapy.
• A clinical trial that checks a sample of the patient's tumor for certain gene changes. The type of targeted therapy that will be given to the patient depends on the type of gene change.

Treatment of progressive or recurrent medullary thyroid carcinoma in children may include the following:

• A clinical trial that checks a sample of the patient's tumor for certain gene changes. The type of targeted therapy that will be given to the patient depends on the type of gene change.