FOREVER CHEMICALS LINKED TO NEARLY DOUBLE THE RATE OF AN AGGRESSIVE BREAST CANCER
Two of the best-known forever chemicals have been linked to a sharply higher rate of an aggressive form of breast cancer, according to a major new study published this week.
The research, led by scientists at the US National Institutes of Health (NIH), was published in the Journal of Clinical Oncology and shared on November 12.
It found that women with the highest levels of two chemicals called PFOA and PFOS in their blood had a noticeably higher rate of oestrogen receptor-negative breast cancer.
That is a type of breast cancer that tends to be harder to treat, because it does not respond to hormone therapies.
What are forever chemicals?
PFAS, short for per- and polyfluoroalkyl substances, are a large family of man-made chemicals.
They earned the nickname forever chemicals because they break down incredibly slowly, both in the environment and in our bodies.
For decades they were used in non-stick cookware, water-repellent clothing, stain-resistant carpets, some food packaging and firefighting foams.
PFOA and PFOS are two of the older, so-called legacy chemicals in this family.
They have been largely phased out, but the researchers note they are still measurable in most people.
What the forever chemicals study found
The team used data from the Sister Study, a long-running project that enrolled 50,884 women aged 35 to 74 in the United States and Puerto Rico between 2003 and 2009.
Every woman was cancer-free when she joined, and each had a sister who had been diagnosed with breast cancer.
Crucially, the researchers tested blood samples that had been collected years before any diagnosis.
They compared 1,609 women who later developed breast cancer with 2,269 women who did not, measuring 17 different PFAS.
Women in the highest exposure group for PFOS had a 93 per cent higher rate of oestrogen receptor-negative breast cancer than those in the lowest group, which is nearly double.
For PFOA, the highest exposure group had a 67 per cent higher rate.
Interestingly, there was no clear link between either chemical and breast cancer overall.
Lead investigator Dr Alexandra White said more research is needed, particularly into the newer replacement chemicals.
Keeping it in perspective
It is important to know this was an observational study, so it shows an association rather than proof that these chemicals cause cancer.
The percentages also describe differences between groups, not any one woman's personal risk.
The study did not test how the chemicals might affect the body, although changes to gene activity and the immune system are possible explanations the scientists want to explore.
First author Dr Che-Jung Chang offered a hopeful note, saying exposure is "still potentially modifiable".
In other words, there are things we can do.
Forever chemicals in Australia
Australians will be pleased to know our drinking water is closely watched.
In June 2025, the National Health and Medical Research Council updated the Australian Drinking Water Guidelines, setting new limits for PFOA, PFOS and two other PFAS.
When the draft limits were first released, a water expert told Cosmos magazine that very little Australian water is affected by PFAS.
The guideline values are also based on drinking water every day over a whole lifetime, so a short-term reading above the limit is not the same as a toxic dose.
If you are worried about your local supply, your water provider is the best place to start.
Simple ways to cut your exposure
You do not need to throw out your whole kitchen, but a few gentle swaps can help.
When an old non-stick pan is scratched or flaking, consider replacing it with stainless steel, cast iron or ceramic.
Choose fresh food over heavily packaged takeaway where you can, as some grease-resistant packaging has used PFAS.
Check labels on new rain jackets, outdoor gear and carpets for "PFAS-free" claims.
Keep up the basics too: regular breast checks, knowing what is normal for you and booking your mammogram when you are eligible.
If you have a family history of breast cancer, or simply want to talk through your risk, speak to your GP.
You can read the full summary of the research on ScienceDaily.
