Parabens are commonly used as preservatives in some, but not all, cosmetics, food products and pharmaceuticals, and underarm cosmetics had come into the firing line as a cause for breast cancer, however this new find has shown traces of the chemicals in breast tissue samples from all of the women in the study.
"Our study appears to confirm the view that there is no simple cause and effect relationship between parabens in underarm products and breast cancer" said Lester Barr, consultant surgeon at the University Hospital of South Manchester and chairman of the Genesis Breast Cancer Prevention Appeal, which part sponsored the study.
Furthermore, the study results also indicate that there is no new, or existing, cause for concern, regarding the safety of parabens.
Jessica Harris, health information manager at Cancer Research UK, spoke to the Cosmetic Toiletry and Perfume Association (CTPA) about the study, questioning some of the findings.
“Although they found parabens in samples of breast tissue, they also found parabens when they ran the experiment with no tissue samples at all - and sometimes at higher levels than they found in the tissue itself. Because of this, the study can’t be used to draw any conclusions about either women’s exposure to parabens, or the effects of parabens on breast cancer risk," she said.
The research, published in the Journal of Applied Toxicology, examined breast tissue samples were taken from 40 women, with the results showing that all of the women had at least one paraben in their tissue.
The 40 women who volunteered for the study, were all undergoing mastectomies between 2005 and 2008 for first primary breast cancer in England.
In total, 160 samples were collected, four from each woman, covering serial locations from the axilla (nearest the armpit) to the sternum (breast bone). The study found 99 per cent of the tissue samples contained at least one paraben and 60 per cent of the samples had five.
A number of studies since 1998 have raised concerns about the potential role of parabens in breast cancer as these chemicals possess oestrogenic properties and oestrogen is known to play a central role in the development, growth and progression of breast cancer.
In particular, a link was proposed between the disproportionate incidence of breast cancer in the upper outer quadrant of the breast and oestrogenic chemicals in that region, with a suggestion this may come from local application of underarm cosmetic products.
Further investigation required
However, this was shown not to be the case, and prompted Barr to comment: "The intriguing discovery that parabens are present even in women who have never used underarm products raises the question: where have these chemicals come from?"
The research found there was a disproportionate incidence of breast cancer in the upper outer quadrant nearest the armpit and significantly higher levels of n-propylparaben were detected in the axilla region, closest to the armpit, than in the mid or medial regions. The other four parabens were equally distributed across all parts of the breast.
"The fact that parabens were detected in the majority of the breast tissue samples cannot be taken to imply that they actually caused breast cancer in the 40 women studied," said Dr Philippa Darbre, Reader in Oncology at the University of Reading, who also led the 2004 study.
"However, the fact that parabens were present in so many of the breast tissue samples does justify further investigation."