Parathyroid cancer

Causes

The parathyroid glands manage the calcium levels in the body. There are four parathyroid glands, two on top of each lobe of the thyroid gland. They are located at the base of the neck.

Parathyroid cancer is an extremely rare type of cancer. Men and women are equally affected. It usually occurs in people older than 30.

The cause of parathyroid cancer is unknown. People with a genetic condition called multiple endocrine neoplasia type I have an increased risk for this disease. People who had head or neck radiation may also be at increased risk. Such radiation exposure, however, is more likely to cause thyroid cancer.

Symptoms

Symptoms of parathyroid cancer are mainly caused by high levels of calcium in the blood (hypercalcemia), and may affect different parts of the body. They include:

• Bone pain
• Constipation
• Fatigue
• Fractures
• Frequent thirst
• Frequent urination
• Kidney stones
• Muscle weakness
• Nausea
• Poor appetite
• Vomiting

Exams and Tests

Parathyroid cancer is very hard to diagnose.

Your doctor will perform a physical exam and ask about your medical history.

About half of the time, feeling the neck with the hands (palpation) can reveal a cancerous parathyroid tumor.

Cancerous parathyroid tumors tend to produce very high amounts of parathyroid hormone (PTH). Tests for this hormone may include:

• Blood calcium
• Blood PTH

Before surgery, you will have a special radioactive scan of the parathyroid glands. The scan is called the sestamibi scan. You may also have a neck ultrasound. These tests are done to confirm which parathyroid gland is abnormal.

Treatment

The following treatments may be used to correct hypercalcemia due to parathyroid cancer:

• A drug that lowers levels of calcium in the blood (gallium nitrate)
• A natural hormone produced by the body that helps control calcium levels (calcitonin)
• Drugs that stop the breakdown and reabsorption of bones into the body, such as pamidronate or etidronate (bisphosphonates)
• Fluids through a vein (IV fluids)

Surgery is the recommended treatment for parathyroid cancer. Sometimes it may be hard to determine whether a parathyroid tumor is cancerous. Your doctor may recommend surgery even without a confirmed diagnosis. Minimally invasive surgery, using smaller cuts, is becoming more common for parathyroid disease.

If tests before the surgery can find the affected gland, surgery may be done on one side of the neck (unilateral). If it is not possible to find the problem gland before surgery, the surgeon will look at both sides of your neck.

Chemotherapy and radiation do not work very well in preventing the cancer from coming back, although radiation can sometimes help reduce the spread of cancer to the bones. Repeated surgeries for cancer that has returned may increase survival rate and reduce the severe effects of hypercalcemia.

Outlook (Prognosis)

Parathyroid cancer is a rare cancer. The tumor is slow growing. Surgery may help extend life even when the cancer spreads.

Possible Complications

The cancer may spread (metastasize) to other places in the body, most commonly the lungs and bones.

The most serious complication of parathyroid cancer is hypercalcemia. Most deaths from parathyroid cancer occur as a result of severe, difficult to control hypercalcemia, and not the cancer itself.

The cancer commonly comes back (recurs). Additional surgeries may be needed. Complications from surgery can include:

• Hoarseness or voice changes as a result of damage to the nerve that controls the vocal cords
• Infection at the site of surgery
• Low levels of calcium in the blood (hypocalcemia), a potentially life-threatening condition
• Scarring

When to Contact a Medical Professional

Alternative Names

Parathyroid carcinoma

References

Bringhurst R, Demay MB, Kronenberg HM. Hormones and disorders of mineral metabolism. In: Williams Textbook of Endocrinology. 11th ed. Philadelphia, Pa: Saunders Elsevier; 2008:chap 27.

Wysolmerski JJ, Insogna KL. The parathyroid glands, hypercalcemia, and hypocalcemia. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 266.

Update Date: 3/22/2012

Updated by: Shehzad Topiwala, MD, Chief Consultant Endocrinologist, Premier Medical Associates, The Villages, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.