Definition

     Thyroid cancer is a disease of the thyroid gland in which the cells become abnormal and form tumors. Thyroid cancer is a rare type of cancer.

Causes

     Experts do not know the exact cause of thyroid cancer.. Thyroid cancer can occur in all age groups. People who have had radiation therapy to the neck are at higher risk. Some thyroid cancers tend to run in families, but most often the cause is unknown and there is no genetic link.

Symptoms

• Enlargement of the thyroid gland

• Neck swelling

• A thyroid nodule

• Hoarseness or changing voice

• Cough or cough with bleeding

• Difficulty swallowing

     Note: Symptoms may vary depending on the type of thyroid cancer

Screening and Diagnostics

     A physical examination can reveal a thyroid mass or nodule (usually in the lower part of the front of the neck), or enlarged lymph nodes in the neck.

     Tests that indicate thyroid cancer:

• Thyroid biopsy showing anaplastic, follicular, medullary or papillary cancer cells

• Ultrasound of the thyroid showing a nodule

• Thyroid scan showing cold nodule (a nodule that does not light up on scan)

• Laryngoscopy showing paralyzed vocal cords

• Elevated serum calcitonin (for medullary cancer) or serum thyroglobulin (for papillary or follicular cancer)

     This disease may also alter the results of the following tests:

• T4

• T3

• TSH

Treatment

     Treatment varies depending on the type of tumor.

     Surgery is usually the treatment of choice, and the entire thyroid gland is usually removed. If the physician suspects that the cancer has spread to lymph nodes in the neck, these will also be removed during surgery.

     Radiation therapy with radioactive iodine is often used with or without surgery. Radiation therapy with beam radiation can also be used.

     After treatment, patients need to take thyroid hormone to replace what their glands used to make. The dose is usually a little higher than what the 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 third of the patients.

Complications

• Low calcium levels from inadvertent removal of the parathyroid glands during surgery

• Injury to the voice box or nerve and hoarseness after surgery

• Spread of the cancer to the lung or other parts of the body

Prevention   

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