Some evidence suggestsTrusted Source that exposure to per- and polyfluoroalkyl substances (PFAS) may increase the risk of certain cancers, including thyroid cancer.

The results of a 2023 studyTrusted Source suggest that exposure to perfluorooctanesulfonic acid (PFOS), which is a type of PFAS, led to a 56% increased risk of a thyroid cancer diagnosis. Similarly, studies in 2022 and 2023 indicate that individuals living in areas with heavy PFAS contamination in drinking water are at a higher risk of thyroid cancer.

Research notes that PFAS exposure can disrupt thyroid function. As such, it is possible that these chemicals may increase the risk and severity of thyroid cancer. However, a 2024 systematic review and meta-analysis notes that although PFAS exposure is a potential risk factor for thyroid cancer, more research is still necessary to establish a link.

PFASTrusted Source refer to a group of synthetic chemicals that are present in many consumer products. This may include food and water, food packaging, and certain household and personal care products. PFAS can accumulate in the blood, and ongoing research indicates that exposure to PFAS in the environment may relate to harmful health effects in humans.

The International Agency for Research on Cancer (IARC) is part of the World Health Organization (WHO). It conducts research to determine if certain substances are carcinogenic, meaning they have the potential to cause cancer.

Two of the most well-studied PFASTrusted Source are perfluorooctanoic acid (PFOA) and PFOS. As of 2023, the IARC considers PFOA as carcinogenic to humans and PFOS as a possible human carcinogen.