Underarm Products and Breast Cancer: Do They or Don’t They?

A new study detected parabens, a chemical used as a preservative in many cosmetics, in the breast tissue of 40 women who underwent mastectomy for breast cancer. Why is that important? Some have claimed parabens in underarm products might raise the risk for breast cancer, based on evidence the compounds may have weak estrogen-like effects, and estrogen is known to play a central role in breast cancer.

But here was the study’s kicker: researchers also found paraben compounds in the seven women who said they’d never used underarm products, leading a study co-author to say in the journal press release:

“Our study appears to confirm the view that there is no simple cause and effect relationship between parabens in underarm products and breast cancer”

Media outlets seemed understandably perplexed about what to conclude. While many seemed to issue a sigh of relief, others were more skeptical. Time Healthland blogger Laura Blue mischievously said the study “may help to alleviate concerns about underarm products further — or rekindle the worry.”

Why the caution in sending out the “all clear?” The study was not designed to answer the question definitively, so it couldn’t make that conclusion.  Here’s what Michael J. Thun, vice president emeritus of the ACS’s Epidemiology and Surveillance Research department told us.

“I think that the press release misinterprets the point of the study. Its purpose was not to study whether parabens (in general) or underarm deodorants (in particular) affect breast cancer risk. Rather, it examined the levels and anatomic distribution of various paraben compounds in the excised breasts of 40 women with breast cancer. At least one form of parabens was detected in all except two of the 160 samples tested, with at least one sample testing positive in all women. This result could not be compared to breast tissue from women without breast cancer, however, since they don’t have mastectomies.

“The first author acknowledges that the study does not show an association between parabens and breast cancer risk in his quote, ‘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.’

“Rather, the study merely confirms earlier, smaller studies which detected parabens in breast tissue of women with cancer. It shows that parabens can be absorbed (probably from personal care products) and the underarm deodorant is not the only source.”

Virtually every media outlet pointed out that the most important lesson from the study was that the high rate of the presence of parabens justifies further investigation.

You can read more about the issue on our website.