Women with the highest blood levels of the forever chemical
PFOS had a 93% higher rate of ER-negative breast cancer than women with the lowest levels, according to a National Institutes of Health analysis published Nov. 5 in the Journal of Clinical Oncology.
For PFOA, the other compound examined, women in the highest group had a 67% higher rate. The study found no clear association between either chemical and breast cancer overall. The research was led by NIH Stadtman Investigator Alexandra White, Ph.D., at the National Institutes of Health, part of the U.S. Department of Health and Human Services.
Tracking Exposure in the Sister Study
The analysis drew on the Sister Study, a project led by NIH’s National Institute of Environmental Health Sciences that enrolled 50,884 women ages 35 to 74 in the U.S. and Puerto Rico between 2003 and 2009. None had breast cancer at enrollment, but each had a full or half-sister diagnosed with the disease.
Researchers compared 1,609 women who later developed breast cancer with 2,269 who did not, measuring 17 PFAS compounds in blood samples collected years before any diagnosis.
Our findings, which we confirmed using a meta-analysis of prior research, indicate that certain legacy PFAS, including PFOA and PFOS, are associated with a higher risk of ER-negative breast cancer, a more aggressive tumor type with few known risk factors
Alexandra White, NIH Stadtman Investigator who led the study
The figures describe relative differences between exposure groups, not any individual woman’s chance of developing cancer, Medical Daily reported. The study shows an association, not proof that the chemicals cause cancer.
Biology of ER-Negative Tumors
ER-negative tumors lack the receptors that allow the hormone estrogen to help cancer cells grow. These variants typically display greater aggression and poorer prognoses, rendering anti-estrogen treatments like tamoxifen ineffective against them.
These cases make up about 15 percent of all breast cancers, and scientists know less about what raises the risk of this type than of hormone-driven disease.
Because the strongest associations involved tumors without hormone receptors, the authors suggest the chemicals may act through nonhormonal mechanisms, consistent with the evidence that many PFAS are only weak endocrine disrupting chemicals and that other relevant mechanisms, such as epigenetic alterations and immunosuppression, may underlie these associations.
The study did not test those explanations.
Clinical Perspectives
According to Fox News Digital, breast and gynecological cancer specialist Tiffany Troso-Sandoval — who practiced at Memorial Sloan Kettering for upwards of 25 years and is based in New York City — noted that the correlation was isolated to ER-negative malignancies, a known aggressive subtype of cancer,
while adding that the research did not indicate a general elevation in overall breast cancer risk, according to Foxnews.
Maybe consider cooking with stainless steel pots and pans … I recommend not heating up any food in plastic containers, because as you heat these plastics, they tend to leach more of the compounds into our foods.
Tiffany Troso-Sandoval, breast and gynecological cancer specialist
HHS Secretary Robert F. Kennedy Jr. said the results demanded more investigation: Women deserve clear answers about how chemicals in their environment may affect their health. This NIH study links two forever chemicals to a higher risk of ER-negative breast cancer and demands further investigation.
Regulatory Limits
Although most people have measurable levels of PFOA and PFOS in their bodies, both compounds have been largely phased out and replaced with newer PFAS. More research is needed, particularly evaluating the risk of breast cancer associated with newer replacement PFAS chemicals,
White said.
The team also carried out meta-analyses, including the current and prior prospective studies, which showed consistent positive associations of PFOA and PFOS with ER-negative breast cancer.
As noted in a summary by the Georgia Municipal Association, the Environmental Protection Agency maintains legally binding thresholds of 4.0 parts per trillion for PFOS and PFOA in drinking water, though it put forward a proposal in May allowing water utilities to petition for a two-year extension to achieve compliance by April 2031.
As documented by GreaterGood, these conclusions carry substantial significance for populations already disproportionately affected by the condition, noting that Black women in America face higher probabilities of receiving an ER-negative breast cancer diagnosis than white women, frequently at younger ages. The authors say future studies should evaluate people with higher PFAS exposure and groups more affected by ER-negative breast cancer.
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