)
A new study has found a possible link between higher levels of two common "forever chemicals" in the blood and an increased risk of an aggressive form of breast cancer. Researchers found that women with the highest levels of perfluorooctanoic acid (PFOA) had a 67% higher rate of estrogen receptor-negative breast cancer, while those with the highest levels of perfluorooctanesulfonic acid (PFOS) had a 93% higher rate.
PFOA and PFOS belong to a large group of chemicals called per- and polyfluoroalkyl substances (PFAS). They are used in consumer and industrial products and are known as "forever chemicals" because they break down very slowly and can stay in the environment and the human body for years. The findings, published in the Journal of Clinical Oncology, add to the concerns about the possible long-term health effects of PFAS exposure.
What Are 'Forever Chemicals'?
PFAS are a large family of thousands of man-made chemicals. They have been used because they are resistant to heat, water, oil and stains. Some PFAS are used in products such as non-stick cookware, stain-resistant materials, food packaging and other consumer products. PFOA and PFOS are among the older and more studied PFAS. Although their use has been reduced or phased out, they have not simply disappeared. Their persistence means they can still be detected in the environment and in people.
The researchers noted that newer PFAS chemicals have replaced some older ones, but there is still limited information about the long-term health effects of many of these new ones.
What Did The New Study Find?
The researchers examined blood samples collected before breast cancer was diagnosed. They measured 17 different PFAS chemicals and looked at whether exposure levels were linked to breast cancer developing later. The study included 1,609 women who subsequently developed breast cancer and 2,269 women in a comparison group. The data came from the NIH Sister Study, which originally enrolled more than 50,000 women between 2003 and 2009.
The findings included PFOA and PFOS. Compared with women who had the lowest levels, those with the highest PFOA levels had a 67% higher rate of ER-negative breast cancer. For PFOS, the rate was 93% higher. The researchers did not find a clear association between these two chemicals and breast cancer overall. The association was specifically stronger for ER-negative tumours.
Why Is ER-Negative Breast Cancer More Concerning?
Breast cancer is not one single disease. Tumours can differ depending on the receptors present on their cells. In ER-positive breast cancer, cancer cells have receptors that can respond to the hormone oestrogen. ER-negative breast cancer lacks these oestrogen receptors. Because of these biological differences, ER-negative tumours can behave differently and are usually more aggressive. This is one reason why the new findings are important.
How Could PFAS Be Linked To Cancer?
The study did not directly establish how PFOA or PFOS might contribute to breast cancer. However, scientists have proposed several possible biological pathways.
PFAS exposure has been studied in relation to processes such as changes in gene activity, hormone-related effects and alterations in the immune system. The researchers said the fact that the strongest association was seen with ER-negative tumours could suggest that mechanisms other than direct oestrogen signalling may be involved. These possibilities still need to be investigated.
Does This Mean PFAS Exposure Causes Breast Cancer?
No, the findings should not be interpreted as proof that exposure to PFOA or PFOS will cause breast cancer.
The researchers compared groups of women according to their blood concentrations of PFAS and found higher rates of ER-negative breast cancer among those with higher levels of certain chemicals. This is an association, not proof of cause and effect.
The researchers also used blood samples collected before diagnosis, which helps reduce concerns that an undiagnosed cancer could have changed PFAS levels. A meta-analysis of earlier studies also supported an association between PFOA and PFOS and ER-negative breast cancer.
Can You Reduce Your Exposure To PFAS?
The researchers point out that PFAS exposure may be modified. Reducing unnecessary contact with products containing PFAS may help lower exposure over time. However, people should not panic or assume that everyday exposure means they will develop cancer. The study highlights a possible risk factor that requires further research, particularly because newer PFAS chemicals are increasingly being used as replacements for older compounds.
The findings add to growing evidence that long-lasting environmental chemicals may have health effects.
Disclaimer: This content including advice provides generic information only. It is in no way a substitute for a qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.