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Underarm deodorants and breast cancer

The Daily Mail, Mirror and Telegraph published claims that women who use deodorants are putting themselves at risk of getting breast cancer. Their articles (“Why women should avoid using anti-perspirants that could cause breast cancer”; “Deodorant in breast cancer link” and “Breast cancer linked to use of deodorants”) were based on research which found aluminium in cancerous breast tissue. The scientists involved in this study highlighted aluminium as a possible environmental factor in the development of breast cancer and suggest that underarm deodorants were a likely source of the aluminium.

You can read the abstract of the study in the Journal of Inorganic Biochemistry here, as well as the articles in the The Daily Mail, the Mirror and the Telegraph.

Hazel Thornton (Hon. DSc.), honorary visiting fellow at the Department of Health Sciences at the University of Leicester and founding chair of the Consumers’ Advisory Group for Clinical Trials and Dr Sarah Cant, Senior Policy and Information Officer at Breakthrough Breast Cancer respond below.

Hazel Thornton (Department of Health Sciences, University of Leicester) responds:

The authors of the scientific paper that these newspaper articles are based on state that ‘the cause of breast cancer is unknown and is likely to involve a combination of genetic and environmental factors’. Whilst ‘the cause’ of breast cancer is unknown, we do know about several of the risk factors: age; sex; genetic make-up; race; ‘Eastern’ versus ‘Western’ diet (Japanese women who move to USA). Thus, an individual risk factor profile can be determined.

This is a study of 17 breasts obtained from 17 patients in Manchester. We do not know from this account any of the other facts or characteristics of the women who had these mastectomies, for example:

  • Did they all use deodorants?
  • If they did, how often, how long for, what type were they?
  • Were the breasts arbitrarily selected? E.g. consecutive mastectomies?
  • What were the other demographic and pathologic details?
  • How old were the women?

  • Were they pre- or post-menopausal?

  • ER positive or negative?

  • What type of ‘breast cancer’ did they have? (aggressive, DCIS, stage?)

  • Were their genetic details known?

This study of only 17 breasts makes no comparisons either with tissue from other parts of the same patient (difficult to do though this might have been); or with tissue from healthy breasts i.e. there was no ‘control’ group. Credible science involves doing things in a certain way. It is good practice to include a control group in any scientific study; here it would have better allowed for a direct comparison to show whether aluminium was present in normal as well as diseased tissue. The evidence is thus weak, and cannot be ‘ranked’ along with other risk factors, or, indeed, as an individual risk factor, seeing that we are not told what might be ‘normal’.

The authors themselves state that they `have no direct evidence that the aluminium measured in these breast biopsies originated from antiperspirant’.

It is evident from the lack of clarity and context in this study, and from the fact that the authors refer heavily to work that they themselves have done in the past, that a great deal more evidence from well constructed comparisons with more detail and better data support is required before any cause-and-effect conclusions are drawn.

Dr Sarah Cant (Breakthrough Breast Cancer) responds:

There is no reliable scientific evidence to suggest a link between deodorant or antiperspirant use and breast cancer. A large number of scientific studies have investigated breast cancer risk factors, however there is no good evidence to suggest that either deodorant or antiperspirant use or exposure to aluminium can increase the risk of developing this disease. This very small study in the Journal of Inorganic Biochemistry does not provide any further proof.

Breast cancer is a complex disease and its causes are unknown for the majority of the 44,000 women diagnosed each year in the UK. That’s why Breakthrough Breast Cancer supports the Breakthrough Generations Study - the largest study of its kind in the UK to investigate the causes of breast cancer and to gain information on causes that might be preventable.

Read more about known risk factors for breast cancer here

Download Breakthrough Breast Cancer’s factsheet Deodorants, antiperspirants and breast cancer risk: the facts

Author: Sense About Science

Document type: For The Record

Published: 11 September 2007


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