Thyroid Cancer Rates Triple and Scientists Look for Cause


The thyroid is a tiny, butterfly-shaped organ located in the front of your throat and below the cartilage known as the Adam’s Apple. You can develop thyroid cancer when small tumors invade the tissue of the thyroid gland. Your thyroid gland produces several hormones that control numerous bodily functions. Some of these include body weight, body temperature, heart rate, and energy level. Cancerous tumors interfere with hormonal production and can cause several uncomfortable symptoms. The most common ones include:

  • Swelling in the neck caused by a lump or nodule
  • Neck pain that typically starts in the front and may spread to the ears
  • Difficulty swallowing due to the presence of the lump or nodule
  • Persistent cough unrelated to having a cold
  • Difficulty breathing
  • Hoarseness and other changes in the voice that don’t go away

Women receive a diagnosis of thyroid cancer three times as often as men. Common risk factors include a genetic predisposition, previous exposure to radiation, and a diet low in iodine. However, this doesn’t fully explain the threefold increase in the number of people doctors have diagnosed with thyroid cancer in the last 40 years.

Is It a Simple Case of Doctors Catching More Cases?

Thanks to improvements in medical technology, thyroid cancer is detected much earlier than in the past by using fine-needle biopsies and ultrasound. In fact, that’ the reason that some researchers give for the huge increase in diagnosed cases of thyroid cancer.

The threefold increase since 1975 includes slow-growing cases that typically would cause few or no symptoms over the course of a person’s lifespan. These people fall into a category that some doctors refer to as over-diagnosis. Other scientists and medical researchers argue that this explanation for the increase in thyroid cancer is far too simplistic.

What is Behind the Increase in Thyroid Cancer Rates?

In 2013, the National Cancer Institute (NCI) studied the results of 77,000 patients who received a thyroid cancer diagnosis since 1975. The biggest finding from the study was the tripling of people diagnosed with the disease in the 38-year period that the NCI studied. Another major finding that troubled the NCI was the fact that advanced cases of thyroid cancer increased by three percent every year after 1994.

Additionally, the death rate from people diagnosed in the later stages went up each year by one percent.

In terms of the number of people, diagnosed cases of thyroid cancer increased from 4.6 people per 100,000 in the mid-1970s to an average of 14.4 people per 100,000 for each year between 2010 and 2013.

Approximately 75 percent of these cases involved women, with the majority being white women.

The results of the NCI study alarmed researchers and doctors alike. Despite thyroid cancer being one of the least lethal and most treatable forms of cancer, it is killing record numbers of people each year. This is in stark contrast to other types of cancer where researchers are gaining ground and lowering fatalities.

What is Behind the Increase in Thyroid Cancer Rates?

The NCI isolated the growing obesity epidemic as one reason for the increase in thyroid cancer rates. It’s likely no coincidence that the obesity rate also tripled during the nearly 40 years that the NCI investigated. The higher your body mass index (BMI), the more likely you are to develop thyroid cancer as well as several other types of cancer.

If the trend continues unchecked, the American Thyroid Association (ATA) predicts that papillary thyroid cancer will become the third most frequent type of cancer diagnosed in American women. According to ATA and several other sources, one-third of adults in the United States have a BMI greater than 30. This is the clinical definition of obesity.

One of the most surprising findings of the NCI study was that the decrease in the number of adults who smoke has lead to an increase in thyroid cancer rates. Those who smoke have up to a 40 percent less chance of developing thyroid cancer as non-smokers do. However, researchers caution this is no reason to take up smoking as it greatly increases the risk of lung cancer, heart disease, stroke, and other types of cancer.

Over the past 40 years, exposure to pollutants and pesticides has grown at a rate faster than any other time in history. The environment, private homes and businesses, and some foods contain large amounts of chemicals that greatly increase the risk of thyroid cancer. Flammable-resistant chemicals contained in furniture, clothing, and plastics may also contain specific chemicals that are reported to link to thyroid cancer. The reason that these specific pollutants and pesticides pose danger is that they interfere with how the thyroid produces hormones, as well as other functions of the endocrine system.

As with all types of cancer, it’s important to reduce the risks you can control and receive regular check-ups if you have risk factors outside of your control. You can find award-winning preventive care and treatment for thyroid cancer right here at UPMC Western Maryland.

Please note, the information provided throughout this site is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. All content, including text, graphics, images, and video, on or available through this website is for general information purposes only. If you are experiencing relating symptoms, please visit your doctor or call 9-1-1 in an emergency.