Cancer Trends Progress Report

Per- and poly-fluorylaklyl substances (PFAS) are a group of manufactured compounds that consist of carbon-fluoride bonds that make PFAS highly stable and resistant to degradation by metabolic or environmental means. First developed in the 1940s, PFAS became widely popular and are used in a number of commercial, industrial, and consumer applications and products. Some current examples include pesticides, firefighting foams, flame retardants, additives in coatings and paints for buildings, textile products such as repellent coatings, personal care products such as cosmetics and makeup, home products such as non-stick coatings for pans, and the development of electronic and semiconductor products.

With its unique chemical and physical properties, PFAS have been designated as “forever chemicals.” Biomonitoring studies have shown that PFAS are ubiquitous in soil and water, and detected in humans. In both occupational and non-occupational settings, the routes of exposures are ingestion of contaminated food and drinking water, inhalation via air or dust particulate, or dermal contact. PFAS exposure has been reported to be associated with hepatic, cardiovascular, immune, reproductive, and developmental effects in humans and animals. Perfluorooctanoic acid (PFOA), one of the most well-studied PFAS chemicals, is associated with kidney and testicular cancers.

However, much of the scientific knowledge of the risk to humans from PFAS exposure is limited by the nature of how previous studies have been conducted. For example, some human studies did not collect any information on historical exposure. Among those that may have historical exposures, collected biological specimens such as blood, and/or have information of specific outcomes of interest, many were cross-sectional in design and thus were only able to evaluate the associations at one specific point in time. These aspects limit the ability to assess any potential relationships between PFAS exposure and health outcomes in terms of establishing causality. Despite this, the growing evidence and awareness of PFAS and detrimental health effects have motivated physicians, scientists, and public health officials about the importance of additional research and regulatory measures on PFAS.