Scientists identify certain ‘forever chemicals’ as potential risk factor for thyroid cancer

Certain types of “forever chemicals” may be associated with a heightened risk of developing thyroid cancer, a new study has found.

While scientists have previously identified exposure to these compounds, known as PFAS, as a potential contributor to recent surges in thyroid cancer, limited research has investigated the association in human populations, the authors noted.

“We wanted to dive into the potential environmental factors that could be the cause for this rise,” co-corresponding author Maaike van Gerwen, an assistant professor at Mount Sinai’s Icahn School of Medicine, said in a statement.

The researchers, who published their findings Tuesday in The Lancet’s eBioMedicine, decided to explore the connections between thyroid cancer diagnosis and available plasma levels of PFAS, or per- and polyfluoroalkyl substances.

Known for their ability to persist in the body and in the environment, PFAS have already been linked to a variety of illnesses, including thyroid disease, testicular cancer and kidney cancer.

There are thousands of types of PFAS, many of which are common ingredients in household products such as nonstick pans, cosmetics and waterproof apparel.

Thyroid cancer cases in the U.S. on average increased by 3.6 percent annually from 1974-2013, while similar such surges have been reported across the globe, according to the study.

Van Gerwen and her colleagues identified 88 thyroid cancer patients whose plasma PFAS levels were available through BioMe, a medical record-linked biobank housed at Mount Sinai.

The researchers evaluated these individuals alongside 88 matching, noncancer controls — measuring levels of eight types of PFAS in all participant blood samples.

Ultimately, they observed that exposure to PFOS — one of the most notorious types of PFAS — led to a 56 percent increased risk of thyroid cancer diagnosis.

A follow-up analysis of a subgroup of 31 patients confirmed this positive association, while making similar connections with several additional PFAS compounds, including PFNA, PFOPA and PFHxS.

“There is strong biological plausibility linking PFAS exposure to thyroid cancer risk,” the authors stated.

The role of PFAS in transforming normal cells into cancer cells may be rooted in their ability to  interfere with processes such as gene function, immunosuppression, inflammation, metabolism and hormone activity, according to the research.

“The results of this study provide further confirmation for the PFAS health crisis and underline the need to reduce, and hopefully one day eliminate, PFAS exposure,” co-corresponding author Lauren Petrick, an associate professor at Mount Sinai, said in a statement.

Acknowledging that it is “nearly impossible to avoid PFAS in our daily activities,” Petrick stressed the need for more public awareness about the severity of these compounds.

Van Gerwen echoed these sentiments, characterizing PFAS exposure as an issue of “global concern,” given the ubiquity of these compounds worldwide.  

“This study provides critical evidence to support large-scale studies further exploring the effect of PFAS exposure on the thyroid gland,” she added.