MEDIA RELEASE
14th October 2008

IBUPROFEN CUTS RISK OF BREAST CANCER

Use of ibuprofen is associated with a 21 per cent reduction in the risk of developing breast cancer, a new meta-analysis has shown.

There have been many studies of the risk of various cancers among people using NSAIDs. Studies of breast cancer risk have reported conflicting findings and, until now, no exhaustive and statistically analysis of these data has been published.

This analysis of 38 separate studies investigating the risk of breast cancer among nearly 2.8 million NSAID users and controls found an overall risk reduction of 12 percent. (1),(2) There was no difference in risk for low or high levels of use.

A total of eight studies investigated the use of ibuprofen. Again, there was no difference in risk reduction between high and low doses.

The authors investigated the possibility that published studies were biased in favour of a positive result and found no evidence to support this. Their in-depth statistical analysis also took into account the quality of published studies and the variation in their findings.

The possible mechanisms by which NSAIDs may reduce breast cancer risk are discussed in detail in an editorial accompanying this paper.3 In summary, two forms of the enzyme cyclo-oxygenase, COX-1 and COX-2, are primary molecular targets for NSAIDs. In laboratory studies, COX-1 has been shown to promote tumour development and some breast tumours produce high levels of COX-2. Inhibition of both forms may therefore be important to reduce cancer risk. NSAIDs may also have other anti-tumour properties independent of their effects on COX.


Notes for editors
1. This was a meta-analysis of 38 case-control and cohort studies and one randomised clinical trial. The definition of use of NSAIDs was taken as that used in each of the studies; this was categorised as low or high use (high dose or long duration of use) when the data were available. The authors were publicly funded. The citation is: Takkouche B, Reguiera-Méndez C, Etminan M. Breast cancer and use of non-steroidal anti-inflammatory drugs. Journal of the National Cancer Institute 2008;100:1439-47.

2. This meta-analysis included 37 observational studies. These studies are designed to identify associations between treatments (NSAID use) and outcomes (breast cancer risk) and cannot prove a causal link. The analysis included one clinical trial, which can provide evidence of causality; this found no reduction in breast cancer risk with aspirin.

3. Howe LR, Lippman SM. Modulation of breast cancer risk by non-steroidal anti-inflammatory drugs. Journal of the National Cancer Institute 2008;100:1420-3 (this is available free at http://jnci.oxfordjournals.org/cgi/reprint/djn347v1).

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