Why Are Thyroid Cancer Rates Higher Than They Used to Be?

Many more people are diagnosed with thyroid cancer today than in 1980. Learn why, plus symptoms to look out for.

Why Are Thyroid Cancer Rates Higher Than They Used to Be?

The thyroid is a butterfly-shaped gland located in the front of your neck, just below your Adam’s apple. Although it’s small, it serves a host of vital functions.

As a key part of the endocrine system, the thyroid produces, stores and releases hormones affecting every organ in our bodies. It helps control metabolism and body temperature, as well as the functioning of the heart and brain.

The thyroid is also the site of a common form of cancer. Thyroid cancer, an overgrowth of potentially harmful cells, begins in the thyroid gland and can spread to other parts of the body.

More than 44,000 Americans will be diagnosed with thyroid cancer in 2021, according to estimates from the American Cancer Society, and about 2,200 will die of the disease. Although both men and women are susceptible, women are three times more likely to develop it.

Thyroid cancer rates increased significantly between 1980 and 2013, according to the National Cancer Institute, before dropping slightly from 2015 to 2017. We asked Kimberly Vanderveen, MD, a board-certified surgeon with Denver Center for Endocrine Surgery in Colorado, to explain why rates have changed over time, how the disease is detected and what treatment options are available.

Are you at risk for thyroid cancer?
Although thyroid cancer can affect people of any race, gender and age, there are a number of factors that increase your risk, including a family history of the disease and exposure to radiation—especially radiation to the head or neck during childhood.

There are also certain groups of people at higher risk, like women, Asians, Pacific Islanders and people between the ages of 25 and 65.

Detecting the disease
Thyroid cancer screenings aren’t typically done as part of physical exams. In fact, the U.S. Preventive Services Task Force (USPSTF) recommends against routine screenings with ultrasound technology and physical neck examinations in adults without symptoms.

"There is pretty good literature to say that we don't have good screening tests that are cost effective or medically beneficial," Dr. Vanderveen says. “Most of the time, thyroid cancer doesn't have any warning signs or symptoms. It's often found as an accident."

It's not uncommon for doctors to detect early cases of thyroid cancer during ultrasound tests for unrelated issues, like narrowing of carotid arteries in the neck or an overactive parathyroid gland.

While early stages of thyroid cancer are typically symptomless, more advanced forms of the disease may present with some signs and symptoms. Make an appointment with your doctor if you notice:

  • A lump or swelling in the neck
  • Trouble swallowing
  • Constant coughing, not due to a cold or flu
  • Pain in the front of the neck

"By the time people have symptoms, usually thyroid nodules are slightly more advanced," says Vanderveen.

Once a lump is found in the thyroid, your doctor will use imaging tests, like an ultrasound, to gather information about the size, color and location of the mass. An ultrasound cannot determine whether a lump is cancerous. A biopsy is performed, using a thin needle, to detect the potential cancer.

"Approximately 5 percent of thyroid nodules are cancerous, but another 10 percent or so might have some suspicious features on biopsy," Vanderveen says.

Why thyroid cancer rates rose
Though they’ve begun to drop in recent years, instances of thyroid cancer increased greatly between the 1980s and the 2010s. The cause? Researchers have a number of theories.

According to a large 2016 study of thyroid cancer cases published in the New England Journal of Medicine, there were more than 560,000 overdiagnosed cases of thyroid cancer between 1987 and 2007. The study included data from 12 high-income countries, including the United States, England, France and Italy.

What does this mean? Overdiagnosis is the discovery of an illness that would never have caused a problem or resulted in death, even if it went untreated.

Vanderveen says that more advanced testing for other conditions may contribute to the uptick of cases. "We are diagnosing more thyroid cancers because we're doing more medical imaging [for unrelated conditions], and we're finding some cancers that are dormant and may never have affected people," she says.

But this doesn't provide the whole picture. Another body of research suggests an increase in late stage thyroid cancer and mortality rates.

"We're noticing a trend in later-stage disease, as well. We're increasing the total number of cancers, not just the previously undetectable ones," Vanderveen says.

Results from research seem to confirm this theory. A 2017 JAMA study of more than 77,000 people diagnosed with thyroid cancer between 1974 and 2013 suggests advanced-stage thyroid cancer increased at an average rate of 2.9 percent annually. Mortality rates among these patients also climbed by about 1 percent each year.

How doctors treat thyroid cancer
The vast majority of thyroid cancer cases are curable, especially if they haven’t spread to distant areas in your body. After the disease is diagnosed, surgery is typically the first step in treatment.

"At this point in time, the standard of care in the United States is to remove all thyroid cancers, but we have gotten less aggressive in our approaches," Vanderveen notes.

Depending on the severity, a surgeon will either remove a portion of the thyroid or the entire organ. During surgery, if lymph nodes on the neck appear to have been affected, they will also be removed for biopsy.

Although this procedure is fairly safe, there are some risks. Bleeding and infection are among the most common.

Following surgery to remove the entire thyroid, patients will be prescribed a life-long medication regimen to replace the hormones the thyroid previously produced. In addition to helping the body maintain its normal metabolism, hormone replacement therapy can also put a stop to the growth of any remaining cancer cells. When only a portion of the thyroid is removed, hormone medication may not be necessary.

In certain cases, thyroid cancer patients may undergo radiation therapy, chemotherapy, targeted drug therapies or radioactive iodine treatment—a one-time oral medication that destroys remaining thyroid tissue.

Your team of healthcare providers—a combination of surgeons, oncologists and endocrinologists—will help determine the best course of treatment for you or your loved one.

Medically reviewed in February 2021.

Sources:

MedlinePlus. “Thyroid Diseases.” December 11, 2020. Accessed January 14, 2021.
National Cancer Institute SEER. “Cancer Stat Facts: Thyroid Cancer.” 2021. Accessed January 14, 2021.
Centers for Disease Control and Prevention. “Thyroid Cancer.” July 15, 2019. Accessed January 14, 2021.
H Lim, SS Devesa, et al. “Trends in Thyroid Cancer Incidence and Mortality in the United States, 1974-2013.” JAMA. 2017;317(13):1338–1348.
American Cancer Society. “What Is Thyroid Cancer?” March 14, 2019. Accessed January 14, 2021.
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U.S. Preventive Services Task Force. “Screening for Thyroid Cancer: US Preventive Services Task Force Recommendation Statement.” JAMA. 2017;317(18):1882–1887.
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InformedHealth.org. “What is overdiagnosis?” April 20, 2017. Accessed January 14, 2021.
Kristin Jenkins. “Thyroid Cancer Overdiagnosis in Half a Million Patients.” Medscape. August 18, 2016. Accessed January 14, 2021.
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