Painkillers found to reduce breast cancer risk

According to an international study the regular use of popular painkillers such as aspirin and ibuprofen reduces the risk of breast cancer.

The study by researchers from Spain and Canada used data from 2.7 million women and is a review of 38 studies which examined the role of painkillers in breast cancer.

There have been many studies which have looked at the association between painkillers and breast cancer and this latest review combines those results to give a more reliable picture.

The researchers from the University of British Columbia, Vancouver Coastal Health Research Institute, and the University of Santiago de Compostela, suggest as both aspirin and ibuprofen are Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), it is their ability to interfere with inflammation in the human body which appears to be the key.

Two body chemicals which help produce inflammation, COX1 and 2, are thought to be the culprits in the development of cancer because they influence how cells divide and die, the production of new blood vessels that can "feed" tumours, and the body's immune responses.

The research revealed that women taking either aspirin or ibuprofen (Advil) regularly had a lower chance of developing breast cancer compared to those who did not use them at all, while regular ibuprofen use appeared to have the biggest effect.

A separate analysis for aspirin showed a 13% relative risk reduction in breast cancer and an analysis for Advil showed a 21% relative risk reduction.

Experts however do warn about the long-term use of painkillers as they can have serious side-effects in particular, anti-inflammatory drugs.

Dr Mahyar Etminan, from the University of British Columbia, who led the research, says the results were "encouraging" and could help scientists understand the complex origins of breast cancer but he warns against women adopting painkillers as part of a cancer prevention lifestyle.

Dr Etminan says this is not recommended routine use of NSAIDs for breast cancer prevention until large randomised trials confirm these findings, which will be available next year.

The regular use of painkillers can cause serious side-effects, including stomach ulcers, increased risk of stroke, asthma and heart, liver and kidney problems in some people and the potential benefits of reducing breast cancer risk would have to be balanced against these.

Breast Cancer groups say women who are worried about their breast cancer risk should talk to their GP rather than simply take painkillers.

The research is published in the Journal of the National Cancer Institute.