Thyroid Health

Sizing Up Thyroid Cancer

September 6, 2005—William H. Rehnquist, age 80, died of thyroid cancer late Saturday night. His death has sparked interest in this relatively uncommon hormonal cancer, which affects about 20,000 people a year.

The thyroid is a gland located in the neck, between the voice box and the collarbones, that releases hormones that affect the body's metabolism. While most cases of thyroid cancer are curable, there are forms of the disease that can progress rapidly.

Types of Thyroid Cancer
In thyroid cancer, a malignant nodule, or mass, grows on the thyroid gland. If a cancerous nodule becomes large enough, it can cause difficulty with breathing and swallowing and make the voice hoarse. Thyroid cancers are not usually painful, though they can be if there is bleeding within the nodule.

Yet most nodules are not cancerous. "More than 90 percent of thyroid nodules are benign," says James Fagin, MD, the director of the division of endocrinology at the University of Cincinnati in Ohio and a spokesperson for the American Thyroid Association. "When they do prove to be thyroid cancer, they, as a rule, carry a very favorable prognosis."

If a patient or doctor finds a thyroid nodule, a type of biopsy known as a fine needle aspiration should be performed to withdraw cells from the nodule and determine whether the nodule is cancerous—and, if so, what type of thyroid cancer it is. A blood test to measure levels of the thyroid hormone may also be taken to rule out other thyroid disorders.

There are four primary types of thyroid cancer. About 80 percent of all thyroid cancers are papillary thyroid cancers, which develop in the cells that make the thyroid hormone. Papillary cancer has a cure rate of 90 to 95 percent, though Dr. Fagin says "it is more serious in older patients." While its cure rates are not as high, follicular thyroid cancer, which develops in the same cells, is still considered very treatable. Medullary thyroid cancer makes up about 5 to 10 percent of all cancers and is more likely to spread to other parts of the body.

Anaplastic thyroid cancer, which mostly occurs in people over age 65, is the most rare—and the most deadly—form of the disease. "It is one of the most rapidly fatal cancers we know of," Dr. Fagin says. "It tends to be very locally invasive; it invades the neck structures and compromises the airways."

Chief Justice Rehnquist has not announced what type of thyroid cancer he has.

Zapping It
Surgery to remove the cancer is the first step in treating thyroid cancer. Most people are then treated with radioactive iodine, which is usually given in liquid form. The radioactive iodine is absorbed by the thyroid and kills remaining cancer cells in the thyroid tissue.

Other options are external radiation, which is delivered via X-ray beams, and hormone therapy. According to Dr. Fagin, thyroid cancers tend not to respond well to chemotherapy, though that therapy may be given in some cases.

Are You At Risk?
While anyone can develop thyroid cancer, women are two to three times more likely than men to develop thyroid cancer, and men and women with a family history of the disease appear to have an increased risk of it. Most people with thyroid cancer are over age 40.

Exposure to radiation, particularly as a child, is a leading risk factor for thyroid cancer. Such exposure may be from radioactive fallout, such as following the Chernobyl accident, or from radiation treatments to the head and neck that one might receive to treat other disease, such as lymphoma.

"People with a history of exposure to a history of radiation should see a physician regularly to have their neck examined with a physical exam or an ultrasound," Dr. Fagin says. "But we do not recommend ultrasound to the population at large because it would lead to a lot of unnecessary worry and surgery."

Most people are screened for thyroid nodules during regular check-ups when their doctor inspects and feels the neck. But if you have a nodule on your neck, or are having problems swallowing or breathing, don't wait for your next check-up, Dr. Fagin says. While the nodule is likely to be benign, a biopsy may be needed to make sure.