Thyroid cancer - papillary carcinoma

Alternative names
Papillary carcinoma of the thyroid

Definition
Papillary carcinoma of the thyroid is the most common cancer of the thyroid gland. Other types of Thyroid cancer include: anaplastic carcinoma of the thyroid, follicular carcinoma of the thyroid, medullary carcinoma of the thyroid, and lymphoma of the thyroid.

Causes, incidence, and risk factors

About 70-75% of all thyroid cancers diagnosed in the United States are papillary carcinoma. It is more common in women than in men.

The cause of this cancer is unknown. Mutations that effect cell growth in the thyroid may play a role.

Exposure to external radiation to the neck increases the risk of developing thyroid cancer, and that risk remains elevated for about 20 years after exposure to high-dose radiation. Intravenous exposure to radiation for medical tests and treatments, does not increase the risk of developing thyroid cancer.

Symptoms

Thyroid cancer usually begins as a nodule (small lump or bump) in the thyroid gland. The diagnosis is made by fine-needle aspiration. However, it should be emphasized that most thyroid nodules (90%) are benign (harmless and noncancerous).

Signs and tests

A thyroid nodule should be evaluated by blood work and a thyroid ultrasound. Any nodule which is greater that 1.0 cm on ultrasound should be further evaluated with fine needle aspiration (FNA).

FNA is used to determine if a nodule in the thyroid gland is cancerous or benign. A needle is inserted into the nodule, and a small amount of tissue is taken into the needle. The procedure can be done in the office or with ultrasound guidance.

Thyroid function tests are usually normal in patients with thyroid cancer.

Treatment

There are three parts to thyroid cancer treatment - surgery, radioactive iodine, and medication. The hospitals best equipped to treat thyroid cancer are the large academic centers.

The surgeons and endocrinologists at these centers see many patients with thyroid cancer and are experts in operating on and treating this cancer. They are also up-to-date on the latest developments for treatment of cancer.

     
  • Surgery should be performed to remove as much of the tumor as possible. The size of the tumor will dictate how much of the thyroid gland is removed. Frequently, the entire thyroid gland is removed.  
  • After the surgery, most (but not all) patients are treated with radioactive iodine, which targets any leftover thyroid tissue and destroys it. This also helps in imaging to look for additional cancer.  
  • If surgery is not an option, external radiation therapy can be useful.  
  • If the cancer has spread to other parts of the body, it can be treated with surgery to alleviate compression on bones or nerves by large tumors.  
  • After surgery, the patient will need to take replacement thyroid hormone for life. This medication is called levothyroxine sodium.

Routine follow-up after treatment involves blood tests every 3 to 6 months, and a radioactive iodine (I-131) scan at 9 to 12 months and then yearly.

Expectations (prognosis)

Ten-year prognosis for papillary cancer of the thyroid is good. About 95% of adults with this cancer survive 10 years. The prognosis is better for patients younger than 40 and for those with smaller tumors.

Soft-tissue invasion by the cancer, large tumors, being older than 40, and the presence of distant metastases (cancer that has spread to distant parts of the body) are worse prognostic signs.

Complications

     
  • After the thyroid gland has been removed, replacement of thyroid hormone with a drug called levothyroxine is required. One must take this for life. Other complications include accidental removal of the parathyroid glands (a gland involved in regulating calcium levels), and damage to a nerve that controls the vocal cords.  
  • Rarely, spreading of cancer to Lymph nodes or through blood vessels to other sites (metastasis) occurs.

Calling your health care provider

Call for an appointment with your health care provider if symptoms of this disorder occur.

Call for an appointment with your health care provider if you have had a thyroidectomy and new symptoms develop, including muscle twitching, cramps, or changes in your voice.

Johns Hopkins patient information

Last revised: December 7, 2012
by Sharon M. Smith, M.D.

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