People in their 40s could reduce their risk of cancer in later life with a regular dose of aspirin, it was claimed today.
Taking aspirin for at least 10 years before cancers normally develop would maximise the drug’s effect, scientists from the charity Cancer Research UK said.
They reached their conclusion after reviewing evidence from several dozen studies involving more than 50,000 participants.
Previous research suggested that people taking aspirin were less likely to develop bowel, breast and possibly other cancers including prostate.
Aspirin blocks the effects of COX enzymes, proteins that help trigger inflammation and are associated with a number of different types of cancer.
Doctors tend to advise against healthy people taking aspirin on a long-term basis because it can cause bleeding in the gut and stomach ulcers.
But the Cancer Research UK team pointed out that common cancers tended to develop after the age of 60, which is also when aspirin is most likely to have bad side effects.
Professor Jack Cuzick, from the Cancer Research UK Centre for Epidemiology at Queen Mary, University of London, said: “Taking aspirin regularly in your mid-40s could maximise the effect this drug has on preventing cancer.
“Taking aspirin at this age, which is about the time pre-cancerous lesions usually begin to develop, may be the best time to stop the disease from progressing to actual cancer.
“And, as the risk of serious side effects of aspirin greatly increase after 60-years-old, taking long-term treatment before this age will help to minimise these side effects.”
But he added it was still too early to recommend regular use of aspirin for cancer prevention.
“Future research and more clinical trials are needed to better identify those people who are at high risk of developing cancers and at low risk of side effects, who will benefit most from aspirin treatment,” Prof Cuzick said.
“Some studies did not show a preventative effect, but the follow up was less than 10 years, so it may have been too early to see the effect.”
For older patients – who are already taking aspirin for cardiovascular disease - the drug may also provide protection against cancer, he said. But it was not yet known whether ’baby aspirin’ could achieve this, or if the full standard dose of 300 milligrams a day would be needed.
The scientists also found that taking aspirin in combination with other drugs known as proton pump inhibitors could lower the risk of stomach bleeding.
A trial called AspECT, funded by Cancer Research UK, is investigating the use of proton pump inhibitors and aspirin in patients with Barrett’s oesophagus – a pre-cancerous condition that can develop into gullet cancer.
Dr Lesley Walker, the charity’s director of cancer information, said: “We need scientists to focus their efforts on how to reduce the side effects of taking aspirin so that very soon it may be possible to use the drug as a way of preventing cancer.
“It’s too soon to recommend that people take aspirin to try and stop cancer developing because of the side effects. But survival is low for cancers like gullet cancer so understanding how to prevent the disease is crucial. It’s important that any decision to take aspirin regularly is only made in consultation with a GP.”