Thyroid Cancer: Vital Facts on Detection, Risk Factors

Until recently, thyroid cancer was the most rapidly rising cancer in the U.S., largely because of increased detection, says the American Cancer Society (ACS).

The number of thyroid cancer cases diagnosed over the last 40 years has tripled. The death rate for thyroid cancer increased slightly from 2008 to 2017 (0.6 percent per year). But the ACS says the death rate appears to have stabilized in recent years.

Thyroid cancer is commonly diagnosed at a younger age than most other adult cancers. And women are three times more likely to develop thyroid cancer than men. (January is Thyroid Awareness Month.)

The thyroid gland makes hormones that help regulate a person’s metabolism, heart rate, blood pressure, and body temperature.

“The vast majority of the increased incidences are papillary thyroid cancers, which tend to be small and indolent and unlikely to shorten a patient’s life,” said Robert Udelsman, M.D., chief of endocrine surgery and director of the endocrine neoplasia institute at Miami Cancer Institute.

Nearly 53,000 new cases of thyroid cancer will be diagnosed in the U.S. this year, according to the American Cancer Society. The disease is more common in women, with more than 40,000 of those new diagnoses expected to occur in females.

Much of the increase is attributed to a higher rate of diagnoses, which mostly stem from a dramatic rise in the use of high-quality diagnostic technology, such as ultrasound and fine-needle biopsies, Dr. Udelsman says. Many thyroid cancers are found incidentally when a patient has a CT scan or ultrasound of the neck for a reason unrelated to the thyroid, such as trauma or a look at the carotid artery, he adds.

Thyroid Cancer Risk Factors

There are certain risk factors for thyroid cancer that are broadly accepted, according to the National Cancer Institute. They include:

Gender and Age: For unclear reasons, thyroid cancers, like almost all diseases of the thyroid, occur about three times more often in women than in men. It can occur at any age, but the risk reaches its peak earlier for women, who are most often in their 40s or 50s when diagnosed, than for men who are usually in their 60s or 70s.

A Diet Low in Iodine: Follicular thyroid cancers are more common in countries where diets are low in iodine. In the United States, most people get enough iodine.

Radiation: Exposure to radiation is a proven risk factor for thyroid cancer. Sources include certain medical treatments like multiple CT scans. Having had head or neck radiation treatments as a child is also a risk factor for thyroid cancer. Risk depends on how much radiation was given and the age of the patient at the time of exposure.

Family History: Most people who develop thyroid cancer do not have an inherited condition or a family history of the disease. However, about one out of three medullary thyroid carcinomas (MTCs) result from inheriting an abnormal gene. Rare cases of papillary thyroid carcinoma also have a genetic predisposition.

Thyroid Cancer Treatment

Despite the uptick in cases, not every thyroid cancer requires surgery or other aggressive medical intervention, according to Dr. Udelsman. He says it’s important that each case receive a detailed review by a specialist, either an endocrinologist or a surgeon specializing in endocrinology.

Thyroid cancers that are less than one centimeter in size can usually be watched and monitored, Dr. Udelsman says. Those that are larger than one centimeter usually necessitate intervention. The most common intervention is surgery to remove either the thyroid lobe containing the cancer (thyroid lobectomy) or the whole thyroid gland (total thyroidectomy). It is also common to remove lymph nodes located near the thyroid gland at the time of surgery.

“A person’s age and lifestyle are important factors to consider when making treatment recommendations,” said Dr. Udelsman. “The good news is the prognosis for most thyroid cancer patients is excellent as 95 percent of them will outlive their disease.”