Why Are Thyroid Cancer Rates On the Rise?

Why Are Thyroid Cancer Rates On the Rise?

Rates are higher in women—but should you be worried?

The thyroid is a small, butterfly-shaped organ located in the front of your neck, just below your Adam’s apple. And while it doesn’t take up a lot of space—most people can't see or feel it—it can be home to a host of problems including hyperthyroidism and thyroid cancer, a condition that's been on the rise in recent decades.

According to the most recent data, collected in 2014, about 48,000 Americans were diagnosed with thyroid cancer, and approximately 1,800 of those cases were fatal. Although both men and women are susceptible to the disease, women are three times more likely to develop this form of cancer.

Thyroid cancer rates haven't always been this high. By comparison, rates increased by about 3.6 percent each year over a span of nearly 40 years (from 1974 to 2013), according to a 2017 study published in the Journal of the American Medical Association (JAMA).

We asked Kimberly Vanderveen, MD, a board-certified surgeon with Denver Center for Endocrine Surgery in Denver, Colorado and affiliate of Rose Medical Center, to weigh in on why thyroid cancer is on the rise, how the disease is detected and what treatment options are available. Here's what she had to say. 

A gland with many functions
The thyroid is an endocrine gland that produces, stores and releases hormones that affect the function of literally every organ in our bodies: It helps control your metabolism, heart, body temperature and mental function. Thyroid cancer, an overgrowth of potentially harmful cells, begins in the thyroid gland and can spread to other parts of the body

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 can increase your risk, including a family history of the disease and exposure to radiation.

There are also certain groups of people at higher risk, like women, Asians 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 US Preventative 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," 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 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. 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 or not 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 it's on the rise
The instances of thyroid cancer have been increasing. 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 of any condition is characterized by the discovery of an illness that would never have caused a problem or resulted in death, even without medical treatment.

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

There likely isn’t one single cause for the rise of thyroid cancer incidences across the globe, but overdiagnoses may be a contributing factor.

How doctors treat thyroid cancer
After thyroid cancer is diagnosed, surgery is typically the first step in treating the disease.

"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 which removes the entire thyroid, patients will be prescribed a life-long medication regimen to replace the hormones the thyroid no longer produces. 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 supplements may not be necessary.

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

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 January 2018.

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