Aspirin 'cuts bowel cancer risk'

28^th October 2011 - Doctors have found many uses for aspirin over the years, beyond its use as a painkiller. Now a study has found it can help protect against hereditary bowel cancer when taken in large doses.

One leading UK cancer charity has described the research as "really important".

Lynch syndrome

Lynch syndrome is a genetic fault that makes someone more likely to develop colorectal cancer (bowel cancer) and other cancers. Researchers say at least one in 1000 people have this condition in the UK and they are about 10 times more likely to develop cancer, often at an early age.

Lynch syndrome accounts for around one in 30 bowel cancer cases.

Bowel cancer protection from aspirin

An international study led by researchers from Newcastle University has found long term aspirin use leads to a 60% reduction in colorectal cancers in people with the genetic fault. Their findings are published online first in The Lancet.

The research involved 43 medical centres in 16 countries and 861 Lynch syndrome patients over as long as 10 years. Around half the patients took two aspirin tablets (600 mg) every day for at least two years. The other half had dummy, or placebo, pills.

Study results

Early results from the trial were not conclusive but the longer patients took aspirin the more of a difference researchers saw in bowel cancer cases. Following up patients around four and a half years from the start of the trial, there were 19 cancers in the aspirin group and 34 on the dummy treatment.

Looking at people who'd taken the aspirin and dummy treatment for two years, there were 23 colorectal cancers in the dummy treatment group and 10 colorectal cancers in the aspirin group - around a 60% reduction.

When the researchers looked at all cancers, not just bowel cancers, the figures were 19 for those who took aspirin and 38 for those who didn't.

Side effects

Were there side effects from such a large daily aspirin dose? The trial was lead by Professor Sir John Burn, Professor of clinical genetics at Newcastle University. He told a news conference: "Surprisingly we had 11 people in our treatment group who got GI [gastrointestinal or stomach] bleeds or ulcers and nine people in the placebo group."

He puts this low figure down to the generally low age of the people taking part, averaging about 45. Also, those who knew they were sensitive to aspirin ruled themselves out of the trial before it started.

He estimates there are about 30,000 people in the UK with Lynch syndrome who could be treated with aspirin. "If we were to put them all on two aspirins a day now, then over the next 30 years or so we would prevent about 10,000 cancers," Sir John says, "but on the other hand we'd cause 1,000 ulcers. There's a trade-off there."