"Forever" Chemical Levels Higher in Women With Ovarian, Breast, Other Cancers

Women with ovarian, breast, skin, and uterine cancers were found to have significantly higher levels of "forever" chemicals in their bodies, according to research published in the Journal of Exposure Science and Environmental Epidemiology.¹

Forever chemicals are per- and polyfluoroalkyl substances (PFAS), which are manmade chemicals commonly found in everyday items, especially in products that are heat, oil, stain, grease, and water resistant, according to the CDC.² The study also looked at phenols like bisphenol A (BPA), as well as parabens.

Using data from the National Health and Nutrition Examination Survey (NHANES), researchers evaluated cross-sectional associations between these forever chemicals and cancer diagnoses. This was done by measuring the levels of 7 PFAS and 12 phenols and parabens, along with self-reported diagnoses of melanoma, thyroid, breast, ovarian, uterine, and prostate cancers among nearly 50,000 adults aged 20 years and older.

The 7 PFAS included were perfluorohexane sulfonic acid (PFHS), 2-(N-methyl-PFOSA) acetic acid (MPAH), perfluorodecanoic acid (PFDE), perfluorononanoic acid (PFNA), perfluoroundecanoic acid (PFUA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS). The 12 phenols and parabens were BPA, benzophenone-3 (BP3), triclosan (TCS), methyl paraben (MPB), ethyl paraben (EPB), propyl paraben (PPB), butyl paraben (BPB), bisphenol-F (BPF), bisphenol-S (BPS), triclocarban (TCC), 2,4-dichlorophenol (DCP24), and 2,5-dichlorophenol (DCP25).

Where PFAS are found | Image credit: Francesco Scatena – stock.adobe.com

In women, a history of melanoma was linked to elevated levels of the following chemicals:

• DCP25 (odds ratio [OR], 2.41; 95% CI, 1.22-4.76)
• PFDE (OR, 2.07; 95% CI, 1.25-3.43)
• DCP24 (OR, 1.85; 95% CI, 1.05-3.26)
• BP3 (OR, 1.81; 95% CI, 1.10-2.96)
• PFUA (OR, 1.76; 95% CI, 1.07-2.89)
• PFNA (OR, 1.72; 95% CI, 1.09-2.73)

“Importantly, melanoma is the fifth most common cancer in the U.S. and recent estimates indicate increasing incidence in higher-income countries,” the study authors said. “While the proportion of melanoma diagnoses is higher among White individuals, survival rates have been shown to be significantly lower among individuals who are Black, Hispanic, Asian American, Native American, and Pacific Islander.”

Additionally, previous ovarian cancer was associated with higher levels of the following:

• DCP25 (OR, 2.80; 95% CI, 1.08-7.27)
• BPA (OR, 1.93; 95% CI, 1.11-3.35)
• BP3 (OR, 1.76; 95% CI, 1.00-3.09)

In cases of previous uterine cancer, PFNA was positively associated (OR, 1.55; 95% CI, 1.03-2.34), while ethyl paraben showed an inverse association (OR, 0.31; 95% CI, 0.12-0.85). Additionally, various PFAS were connected to previous ovarian and uterine cancers among White women, while non-White women demonstrated associations between MPAH or BPF and previous breast cancer.

The study authors made sure to note that these findings do not immediately point to a causal relationship between PFAS and cancer, and that more research is needed to explore that idea.

“While we would have liked to account for the time between cancer diagnoses and biomarker measurement, this information was not available in NHANES,” the authors said. “Further, because our exposures were measured after the cancer diagnoses occurred, reverse causation is a possibility if behavioral changes occurred. Subsequent treatment for cancer may also influence concentrations of endocrine-disrupting chemicals through altered metabolism, which may also be an important source of exposure misclassification among those with previous cancer diagnoses.”

They also noted that the study’s findings show a “sexually dimorphic nature” of risk for melanoma, and a “potential estrogen-dependent mechanism” for both melanoma and ovarian cancer.

“We also showed differential associations between environmental exposures and previous cancer diagnoses by racial groups, underscoring racial disparities that exist both in innate risk of cancer outcomes and in exposures to environmental toxicants,” they said. “Future work in prospective cancer studies should aim to explore the roles of estrogenic chemicals and estrogen disruption in the pathology of melanoma and ovarian cancer and consider racial disparities when evaluating cancer mechanisms and risk."

They also concluded that the findings from this study can help inform and prioritize the types of toxicants that should be targeted by policies for surveillance of chemical exposure, as well as assess risk in communities where there is environmental contamination.

References

1. Cathey AL, Nguyen VK, Colacino JA, Woodruff TJ, Reynolds P, Aung MT. Exploratory profiles of phenols, parabens, and per- and poly-fluoroalkyl substances among NHANES study participants in association with previous cancer diagnoses. J Expo Sci Environ Epidemiol. Published online September 18, 2023. doi:10.1038/s41370-023-00601-6
2. Per- and polyfluorinated substances (PFAS) factsheet. CDC. May 2, 2022. Accessed September 26, 2023. https://www.cdc.gov/biomonitoring/PFAS_FactSheet.html