What Is Thyroid Cancer?

Cancer is a common condition these days. According to the American Cancer Society, nearly half of all men and a third of all women will have some form of cancer in their lifetime. As of 2001, there were approximately 9.8 million Americans still living who had a history of cancer. Cancer is the second leading cause of death in the United States, just behind heart disease.

Any form of cancer is serious, but if you're destined to get cancer, thyroid cancer is one of the better ones to get. Most people are successfully treated and do not die of thyroid cancer.

Like other kinds of cancer, thyroid cancer is the growth of abnormal cells. Unlike healthy, normal cells, these abnormal cells do not die out but multiply, spawning more and more abnormal cells that eventually overwhelm healthy functioning of an organ and spread elsewhere. Fortunately, in most cases of thyroid cancer, these abnormal cells grow relatively slowly.

The Mysterious Cause

The cause of cancer is still largely a mystery. But scientists do know that the root cause is damage to the DNA (deoxyribonucleic acid), the genetic material in every single body cell that carries the instructions for nearly everything our cells do. In a lifetime, it's normal for DNA molecules to experience some damage. Most times, the cell can repair itself. But in cancer cells, the damaged DNA goes unrepaired, and the abnormal cells grow, often causing a malignant, or cancerous, tumor.

A patient's symptoms, treatments, and prognosis depend a great deal on where the cancer is located. Your chances for survival also depend in large part on how early the cancer is detected and treated.


A nodule or lump in the thyroid is one sign that you may have thyroid cancer. But keep in mind that as many as 95 percent of these nodules are benign. See your doctor if you feel or see anything suspicious in your neck.

In people who have thyroid cancer, the prognosis is generally good. According to estimated predictions from the American Cancer Society, approximately 25,690 cases of thyroid cancer were expected in 2005. Of those, 19,190 were expected to occur in women, and 1,490 were expected to eventually be fatal. In other words, only one of sixteen cases of thyroid cancer lead to death due to the cancer. The key is early detection, particularly of unusual lumps and nodules in the thyroid gland.

Who Gets Thyroid Cancer?

Too much sun raises your risk for skin cancer. Smoking cigarettes makes it more likely you'll develop lung cancer. But when it comes to thyroid cancer, there are few specific risk factors that make one person more likely to develop thyroid cancer than the next person. Most people who have thyroid cancer have no apparent risk factors, and some who have at least one risk factor never get the disease.

One factor that does raise your risk of thyroid cancer is exposure to radiation. People who were exposed to radiation in childhood seem more likely to develop thyroid cancer as adults. Years ago, radiation was used to treat acne, fungal infections of the scalp, enlarged tonsils, and adenoids in children. (Note: This type of radiation is different from routine X-rays.) As adults, these people have a higher risk of thyroid cancer. Exposure to local radiation as adults, however, does not appear to be linked to thyroid cancer.

Exposure to radiation from nuclear fallout such as at Chernobyl also increases your risk. The Ukrainian city of Chernobyl was the site of a major nuclear power plant accident in 1986. Many children living in that area went on to develop thyroid cancer. Adults involved in the subsequent cleanup also have a higher than normal rate of thyroid cancer.

Here in the United States, some studies have found a higher incidence of thyroid cancer — as well as other thyroid diseases — in people living near certain nuclear facilities, such as the Hanford nuclear processing facility in Richland, Washington, and testing sites for nuclear bombs in regions such as that outside Las Vegas, Nevada.


According to the American Cancer Society, the incidence of thyroid cancer has been increasing in both sexes since 1980, although the increase is larger in women than it is in men. Between 1980 and 1998, the incidence for men and women combined increased at an average of 2.5 percent per year. Since 1998, thyroid cancer incidence has been increasing at an average of 7.7 percent annually.

Another risk factor is family history. Approximately 5 percent of people who develop papillary thyroid cancer have a relative who had the disease, too. And approximately 20 percent of cases of medullary thyroid cancer are the result of an abnormal gene that is inherited from a parent.

Thyroid cancer is also more prevalent in women than it is in men. Elsewhere in the world, thyroid cancer is more common among people who eat a diet low in iodine. But some people, like Pat, had no risk factors and no signs or symptoms.

Pat learned she had thyroid cancer during a routine doctor visit when her physician felt a lump. She had noticed nothing at all. She decided to have her entire thyroid removed, which turned out to be a good decision. During the surgery, the surgeon found a second tumor on the other side of her thyroid.

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