The updated guidelines (the last revision was in 1996) are based on data that includes outcomes from a national cancer screening effort in South Korea, through which many doctors offered low-cost ultrasound exams of the thyroid as a means of screening for cancer. The availability of thyroid screening contributed to a 15-fold increase in the number of thyroid cancer cases in South Korea between 1993 and 2011. Despite the mass effort to screen more people, there was no improvement in the number of people dying from thyroid cancer. This lead the task force to determine there is not enough evidence to suggest that widespread screening of adults without symptoms of thyroid cancer is beneficial.

First, the good news. According to 2016 American Cancer Society statistics, Americans have a less than one percent chance of developing thyroid cancer in their lifetime. And survival rates are high: 98 percent of patients diagnosed with thyroid cancer are alive five years after diagnosis, according to the American Cancer Society.

However, according to research published earlier this year in the Journal of the American Medical Association (JAMA) by Sosa and others, the incidence of thyroid cancer in the U.S. has increased three percent each year between 1974 and 2013. Some doctors and scientists have argued the increase is largely due to doctors using more imaging, such as ultrasound, CT, and PET scans, which are bringing doctors’ attention to thyroid nodules, even when the nodules are too small to cause symptoms.

Sosa said the data show the U.S. has seen a rise in the incidence and death rates for advanced papillary thyroid cancer, the most common thyroid cancer, which suggests a true increase in the number of people getting thyroid cancer -- not just a case of overdiagnosing small, clinically insignificant thyroid cancer.

The new guidelines suggest adults who don’t have symptoms or signs of thyroid cancer -- a lump or swelling in the front of their neck, along with discomfort or pressure in that area, changes to their voice or difficulty swallowing or breathing -- don’t need to be screened.

People without symptoms who should continue to be screened regularly include those who have received radiation to their face, neck or chest in childhood or adolescence, and those with a family history of thyroid cancer or other rare diseases associated with multiple endocrine neoplasia syndromes, Sosa said. These groups are at higher risk for thyroid cancer.

This information is not prominent in the guidelines, and should be highlighted, Sosa wrote in an editorial published in JAMA Surgery that accompanies the thyroid cancer screening guidelines.

Just as women can conduct self-examinations for changes in the breasts, men and women can take a moment while shaving or putting on jewelry to feel their neck for lumps or other changes.

This is an easy way to be aware of any changes, Sosa said. Even though most lumps turn out to be non-cancerous, people should always feel comfortable calling their doctor with a question or telling them about any changes they have noticed in their body or symptoms they experience, Sosa said.