Does an aspirin a day keep cancer at bay?

reposted from: New Scientist

12:45 8 December 2010

Jessica Hamzelou, reporter

An aspirin a day could protect against a host of cancers. Even low daily doses of the drug have been found to cut the rate of cancer deaths by a third. Given the other strings in the drug's bow, aspirin might be fulfilling its "wonder drug" expectations.

In the study, Peter Rothwell, at the University of Oxford, and colleagues followed up over 25,000 patients enrolled in eight clinical trials assessing the effects of daily aspirin. The group found that even a low dose reduced the rate of cancer deaths by 21 per cent during the trials. What's more, five years later, the rate had dropped by a third.

The effects were also long-lasting. While the trials lasted between four and eight years, a reduction in cancer deaths of 20 per cent was still seen 20 years later in those taking aspirin.

The team also report in The Lancet that the greatest benefits were enjoyed by those who had taken the pill over the longest period of time.

The new findings are likely to boost aspirin's superhero status. Already hailed a "wonder drug", daily aspirin has been suggested to reduce general mortality in women by 25 per cent and is known to reduce the risk of cardiovascular disease and stroke.

This isn't the first time aspirin has been shown to defend against cancers, either. Back in 2002, researchers in New York found that female smokers could cut their risk of lung cancer by a third if they took aspirin three times a week for a month.

A year later an Italian group noted that taking aspirin once a week for five years could slash the risk of mouth, throat and oesophageal cancers by two-thirds, too.

Additional evidence came in the observation that women who reported taking aspirin regularly were 16 per cent less likely to develop cancer than those who didn't. And earlier this year another group noted 25 per cent lower risk of bowel cancer in individuals taking a low dose of aspirin on a daily basis.

The drug is thought to work by inhibiting cyclooxygenase (COX) enzymes, which are involved in inflammation and cancer growth.

But the wonder drug isn't wonderful for everyone. Aspirin is known to irritate the stomach, and can cause gastrointestinal bleeding. And for those entering their seventies, the risks are likely to outweigh the benefits.

Alastair Watson at the University of East Anglia said in a statement:

People wishing to take aspirin should first discuss it with their GP. But this study remains a very important new development in our understanding of how to prevent cancer in general. It is further proof that aspirin is, by a long way, the most amazing drug in the world.