Is there a link between breast cancer and antiperspirant?
Thursday June 19, 2003
This scare started in 1999 with a circular email claiming that toxins were “purged” through perspiration, and that when the armpit sweat glands were blocked, toxins built up in the lymph nodes behind them, causing cancer in the upper outer quadrant of the breast.
While it’s true to say that an excess of cancers occur in this quadrant of breast tissue – the one closest to the lymph nodes – it is also by far the largest area of breast tissue.
Furthermore, sweating is certainly not the primary means by which the body rids itself of toxins. But the email caused so much concern at the time that the American Cancer Society and the National Cancer Institute issued statements to reassure people, and scientists began to study the issue.
If you really want to get to the bottom of whether an environmental factor is causing an illness, it’s good to be able to compare one group who were exposed to your toxin, antiperspirant for example, with a group who weren’t. In 2002 a large study was published looking at 1,600 women and found no link between antiperspirant use and breast cancer. It was testament to the influence of the original “hoax” email (as Harvard medics called it) that they also went out of their way to study its specific claim that shaving before using antiperspirant increased the chances of it causing cancer, because toxic chemicals could get in more easily, and again found no link.
This week the story rose again when Dr Philippa Darbre, a molecular biologist from Reading University, published a speculative hypothesis paper, in a small but respected academic journal, describing the effects of some of the ingredients of antiperspirants on non-living tissue in the laboratory, in other peoples’ experiments. Specifically, that aluminium has been reported to at least bind to DNA, and also to alter gene expression in some situations, and that parabens (preservatives used in some cosmetic creams) have been reported to work similarly to oestrogen in some experiments.
This has certainly generated more media interest than any of her other more eminent papers on, for example, IGF-II receptors and breast cancer, although she tells me that she never sent out a press release, but happened to mention it to a friend who worked for the Sunday Times.
Science is all about testing interesting hypotheses. In this case we have an interesting but half-finished laboratory-based story against a convincingly large study of real people that showed antiperspirants to be safe.
Unfortunately, it looks like the largest risk factors for breast cancer at the moment are the ones we can’t control such as age, sex, and family history; or the ones we might not want to such as smoking and age at childbirth.