Thyroid Cancer

Thyroid Cancer

What is the thyroid?

The thyroid is a gland at the front of your neck beneath your voice box (larynx). A healthy thyroid is a little larger than a quarter. It usually can't be felt through the skin.

The thyroid has two parts (lobes). A thin piece of tissue (the isthmus) connects the two lobes.

The thyroid makes hormones:

·         Thyroid hormone: The thyroid follicular cells make thyroid hormone. This hormone affects heart rate, blood pressure, body temperature, and weight. For example, too much thyroid hormone makes your heart race, and too little makes you feel very tired.

·         Calcitonin: The C cells in the thyroid make calcitonin. This hormone plays a small role in keeping a healthy level of calcium in the body.

Four or more tiny parathyroid glands are on the back of the thyroid. These glands make parathyroid hormone. This hormone plays a big role in helping the body maintain a healthy level of calcium.

What is cancer?

Cancer begins in cells, the building blocks that make up tissues. Tissues make up the thyroid and other organs of the body.

Normal thyroid cells grow and divide to form new cells as the body needs them. When normal cells grow old or get damaged, they die, and new cells take their place.

Sometimes, this process goes wrong. New cells form when the body does not need them, and old or damaged cells do not die as they should. The buildup of extra cells often forms a mass of tissue called a nodule. It may also be called a growth or tumor.

Most thyroid nodules are benign. Benign nodules are not cancer (malignant):

·         Benign nodules:

o    Are usually not harmful

o    Don't invade the tissues around them

o    Don't spread to other parts of the body

o    Usually don't need to be removed

·         Malignant nodules (thyroid cancer):

o    May sometimes be a threat to life

o    Can invade nearby tissues and organs

o    Can spread to other parts of the body

o    Often can be removed or destroyed, but sometimes thyroid cancer returns

Thyroid cancer cells can spread by breaking away from the thyroid tumor. They can travel through lymph vessels to nearby lymph nodes. They can also spread through blood vessels to the lungs, liver, or bones. After spreading, cancer cells may attach to other tissues and grow to form new tumors that may damage those tissues.

What are the different types of thyroid cancer?

There are several types of thyroid cancer:

·         Papillary: In the United States, papillary thyroid cancer is the most common type. About 86 of every 100 people with thyroid cancer have this type. It begins in follicular cells and usually grows slowly. If diagnosed early, most people with papillary thyroid cancer can be cured.

·         Follicular: The second most common type is follicular thyroid cancer. A little more than 9 of every 100 people with thyroid cancer have this type. It begins in follicular cells and usually grows slowly. If diagnosed early, most people with follicular thyroid cancer can be treated successfully.

·         Medullary: Medullary thyroid cancer is not common. About 2 of every 100 people with thyroid cancer have this type. It begins in C cells and can make abnormally high levels of calcitonin. Medullary thyroid cancer tends to grow slowly. It can be easier to control if it's found and treated before it spreads to other parts of the body.

Medullary thyroid cancer sometimes runs in families.

A change in a gene called RET can be passed from parent to child. Nearly everyone with a changed RET gene develops medullary thyroid cancer. The disease occurs alone, as familial medullary thyroid cancer, or with other cancers, as multiple endocrine neoplasia (MEN) syndrome.

A blood test can usually detect a changed RET gene. If it's found in a person with medullary thyroid cancer, the doctor may suggest that family members also be tested. For those who have a changed gene, the doctor may recommend frequent lab tests or surgery to remove the thyroid before cancer develops.

·         Anaplastic: The least common type is anaplastic thyroid cancer. About 1 of every 100 people with thyroid cancer has this type. Most people with anaplastic thyroid cancer are older than 60. The cancer begins in follicular cells of the thyroid. The cancer cells tend to grow and spread very quickly. Anaplastic thyroid cancer is very hard to control.

Tests and treatment options depend on the type of thyroid cancer.

Thyroid cancer symptoms*

·         lumps or nodules in front of the neck (single or multiple)

·         enlarged lymph nodes in the neck

·         problems with swallowing

·         hoarseness or voice changes

·         pain or discomfort in the neck

·         chronic cough

How is thyroid cancer diagnosed?

·         Physical exam: Your doctor feels your thyroid for lumps (nodules). Your doctor also checks your neck and nearby lymph nodes for growths or swelling.

·         Blood tests: Your doctor may check for abnormal levels of thyroid-stimulating hormone (TSH) in the blood. Too much or too little TSH means the thyroid is not working well. If your doctor thinks that you may have medullary thyroid cancer, you'll be checked for a high level of calcitonin and have other blood tests.

·         Ultrasound: An ultrasound device uses sound waves that can't be heard by humans. The sound waves make a pattern of echoes as they bounce off organs inside your neck. The echoes create a picture of your thyroid and nearby tissues. The picture can show thyroid nodules that are too small to be felt. Your 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: Your doctor may order a scan of your thyroid. You swallow a small amount of a radioactive substance (such as radioactive iodine), 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: A biopsy is the only sure way to diagnose thyroid cancer. A pathologist checks a sample of thyroid tissue for cancer cells using a microscope.

Your doctor may take tissue for a biopsy in one of two ways:

·         With a thin needle: Your doctor removes a sample of tissue from a thyroid nodule with a thin needle. An ultrasound device can help your doctor see where to place the needle. Most people have this type of biopsy.

·         With surgery: If a diagnosis can't be made from tissue removed with a needle, a surgeon removes a lobe or the entire thyroid. For example, if the doctor suspects follicular thyroid cancer, the lobe that contains the nodule may be removed for diagnosis.

How is staging determined for thyroid cancer?

If the biopsy shows that you have cancer, your doctor will need to learn the extent (stage) of the disease to help you choose the best treatment.

The stage is based on the size of the nodule and whether the cancer has invaded nearby tissues or spread to other parts of the body. Thyroid cancer spreads most often to nearby tissues in the neck or to lymph nodes. It may also spread to the lungs and bones.

When cancer spreads from its original place to another part of the body, the new tumor has the same kind of cancer cells and the same name as the original tumor. For example, if thyroid cancer spreads to the lungs, the cancer cells in the lungs are actually thyroid cancer cells. The disease is metastatic thyroid cancer, not lung cancer. It's treated as thyroid cancer, not as lung cancer. Doctors sometimes call the new tumor in the lung “distant” disease.

Staging may involve one or more of these tests:

·         Ultrasound: An ultrasound exam of your neck may show whether cancer has spread to lymph nodes or other tissues near your thyroid.

·         CT scan: An x-ray machine linked to a computer takes a series of detailed pictures of your neck and chest area. A CT scan may show whether cancer has spread to lymph nodes, other areas in your neck, or your chest.

·         MRI: MRI uses a powerful magnet linked to a computer. It makes detailed pictures of your neck and chest area. MRI may show whether cancer has spread to lymph nodes or other areas.

·         Chest x-ray: An x-ray of the chest can often show whether cancer has spread to the lungs.

·         Whole body scan: You may have a whole body scan to see if cancer has spread from the thyroid to other parts of the body. You get a small amount of a radioactive substance (such as radioactive iodine). The substance travels through the bloodstream. Thyroid cancer cells in other organs or the bones take up the substance. Thyroid cancer that has spread may show up on a whole body scan.

What is the treatment for thyroid cancer?

Treatment options for people with thyroid cancer are …

·         Surgery

·         Thyroid hormone treatment

·         Radioactive iodine therapy

·         External radiation therapy

·         Chemotherapy

Your doctor may refer you to a specialist who has experience treating thyroid cancer, or you may ask for a referral. You may have a team of specialists:

·         Endocrinologist: An endocrinologist is a doctor who specializes in treating people who have hormone disorders.

·         Thyroidologist: A thyroidologist is an endocrinologist who specializes in treating diseases of the thyroid.

·         Surgeon: This type of doctor can perform surgery.

·         Nuclear medicine doctor: A nuclear medicine doctor specializes in using radioactive substances to diagnose and treat cancer and other diseases.

·         Medical oncologist: A medical oncologist is a doctor who specializes in treating cancer with drugs.

·         Radiation oncologist: A radiation oncologist is a doctor who specializes in treating cancer with radiation therapy.

An oncology nurse and a registered dietitian may also be part of your team.

Your health care team can describe your treatment choices, the expected results of each treatment, and the possible side effects. Because cancer treatments often damage healthy cells and tissues, side effects are common. These side effects depend on many factors, including the type of treatment. Side effects may not be the same for each person, and they may even change from one treatment session to the next. Before treatment starts, ask your health care team about possible side effects and how treatment may change your normal activities.