Aspirin cuts risk of inherited cancer
28 October 2011
Scientists co-funded by the Medical Research Council (MRC) have confirmed that taking a regular dose of aspirin reduces the long-term risk of developing cancer in people with a family history of the disease.
An international collaboration found that cancer risk can be cut by 60 per cent, but that the benefits only become obvious five years after taking the drug. They published the results today in The Lancet.
Evidence that aspirin can reduce cancer risk has been accumulating for more than 20 years, but this is the first time that scientists have used a randomised controlled trial to confirm the drug’s benefit.
Professor Sir John Burn from Newcastle University who led the international research collaboration said:
“What we have finally shown is that aspirin has a major preventative effect on cancer but this doesn’t become apparent until years later. We have succeeded in showing the benefits of aspirin because we had a lot of long term data and because Lynch syndrome is associated with rapid development of cancer. It has also demonstrated how our research community and families with inherited forms of cancer can work together to answer questions important for the whole population.
“Before anyone begins to take aspirin on a regular basis they should consult their doctor as aspirin is known to bring with it a risk of stomach complaints including ulcers. However, if there is a strong family history of cancer then people may want to weigh up the cost-benefits particularly as these days drugs which block acid production in the stomach are available over the counter.”
The study followed almost 1,000 people with Lynch syndrome, an inherited genetic disorder associated with the rapid development of cancer. Around half of people with Lynch syndrome develop cancer, mainly in the bowel and womb.
Between 1999 and 2005, 861 participants began taking either two aspirins (600mg) every day for two years, or a placebo. In 2007, cancer rates in the two groups were similar, but by 2010, almost twice as many people in the placebo group had developed colon cancer than in the treatment group.
Further analysis of participants who took aspirin for at least two years found an even more pronounced effect: a 63 per cent reduction in colorectal cancer with 23 bowel cancers in the placebo group but only 10 in the aspirin group.
Looking at all cancers related to Lynch syndrome, almost 30 per cent of the participants taking the placebo had developed a cancer compared to around 15 per cent of those taking the aspirin.
Professor Tim Bishop from the University of Leeds, whose team was responsible for the statistical analysis, said:
“What surprised us was that there was no difference in the number of people developing polyps which are thought to be the precursors of cancer. But, many fewer patients who had been taking aspirin years before went on to develop cancers. This beneficial effect years later makes sense of all the observational studies — previous randomised trials have not been allowed to run for long enough.”
Professor Nick Hastie, Director of the MRC Human Genetics Unit, said:
“Bowel cancer is the second commonest cause of cancer death in the UK, being responsible for 16,000 deaths a year. This landmark study provides the clearest evidence yet that aspirin can help protect against development of this disease. As we learn more about the underlying mechanism of this anti-tumour effect, we will eventually be able to develop new ways of preventing and treating cancer.”
David Willetts, Minister for Universities and Science, said:
“This groundbreaking study is an excellent achievement for the UK research base and a welcome addition to our robust body of evidence on cancer. It has the potential to save thousands of lives worldwide and is clear evidence of the value of long-term studies showing simple steps that can be taken to improve people's lives.”
The scientists are not sure how aspirin reduces cancer risk but say it might cause genetically damaged cells to die. The team are now preparing a large-scale follow-up trial and want to recruit 3,000 people across the world to test the effect of different doses of aspirin.
The research was funded by the MRC, Cancer Research UK, the European Union, Bayer Corporation, National Starch and Chemical Company, Newcastle Upon Tyne Hospitals NHS Foundation Trust and Bayer Pharma.
