Definition of Thyroid cancer:

Thyroid cancer is a cancer that starts in the thyroid gland. The thyroid gland is located inside the front of your lower neck.

Causes, incidence, and risk factors:

Thyroid cancer can occur in all age groups.

People who have had radiation therapy to the neck are at higher risk. Radiation therapy was commonly used in the 1950s to treat enlarged thymus glands, adenoids and tonsils, and skin disorders. People who received radiation therapy as children are at increased risk for developing thyroid cancer.

Other risk factors are a family history of thyroid cancer and chronic goiter.

There are several types of thyroid cancer:

• Anaplastic carcinoma (also called giant and spindle cell cancer) is the most dangerous form of thyroid cancer. It is rare, and does not respond to radioiodine therapy. Anaplastic carcinoma spreads quickly.
• Follicular carcinoma accounts for about 10% of all cases and is more likely to come back and spread.
• Medullary carcinoma is a cancer of nonthyroid cells that are normally present in the thyroid gland. This form of the thyroid cancer tends to occur in families. It has been linked with several specific genetic mutations. It requires different treatment than other types of thyroid cancer.
• Papillary carcinoma is the most common type, and usually affects women of childbearing age. It spreads slowly and is the least dangerous type of thyroid cancer.

Symptoms:

Symptoms vary depending on the type of thyroid cancer, but may include:

• Cough
• Difficulty swallowing
• Enlargement of the thyroid gland
• Hoarseness or changing voice
• Neck swelling
• Thyroid lump (nodule)

Signs and tests:

Your doctor will perform a physical exam. This may reveal a lump in the thyroid, or swollen lymph nodes in the neck.

The following tests may be done:

• Calcitonin blood test to check for medullary cancer
• Thyroglobulin blood test to check for papillary or follicular cancer
• Laryngoscopy
• Thyroid biopsy
• Thyroid scan
• Ultrasound of the thyroid

This disease may also affect the results of the following thyroid function tests:

• T3
• T4
• TSH

Treatment:

Treatment depends on the type of thyroid cancer.

Surgery is most often done. The entire thyroid gland is usually removed. If the doctor suspects that the cancer has spread to lymph nodes in the neck, these will also be removed during surgery.

Radiation therapy may be performed using external beam (x-ray) radiation or by taking radioactive iodine by mouth. It may be done with or without surgery.

After treatment, you need to take thyroid hormone to replace what your glands used to make. The dose is usually a little higher than what your body needs, which helps keep the cancer from coming back.

If the cancer does not respond to surgery or radiation and has spread to other parts of the body, chemotherapy may be used, but this is only effective for a small number of patients.

Support Groups:

You can ease the stress of illness by joining a support group made up of people who share common experiences and problems. See: Cancer - support group

Expectations (prognosis):

Anaplastic carcinoma has the worst outcome of all the types of thyroid cancer. It is usually deadly despite aggressive treatment.

Follicular carcinomas are often fast growing and may spread to other tissues, but the outlook is still good. Most patients are cured.

The outcome with medullary carcinoma varies. Women under age 40 have a better chance of a good outcome.

Papillary carcinomas are usually slower growing. Most people are cured and have a normal life expectancy.

Patients who have treatment for thyroid cancer must take thyroid hormone pills for the rest of their lives.

Complications:

Complications of thyroid cancer may include:

• Injury to the voice box and hoarseness after thryoid surgery
• Low calcium levels from accidental removal of the parathyroid glands during surgery
• Spread of the cancer to the lungs, bones, or other parts of the body

Calling your health care provider:

Call your health care provider if you notice a lump in your neck.

Prevention:

There is no known prevention. Awareness of risk (such as previous radiation therapy to the neck) can allow earlier diagnosis and treatment.

Sometimes, people with strong family histories and genetic mutations related to thyroid cancer will have their thyroid gland removed for preventative purposes.