British researchers have discovered the first definitive evidence that aspirin reduces overall death rates by a third after just five years’ use.
Rates were slashed by half for some cancers and the longer people took the drug, the better the protection.
The study has led to the 100-year-old painkiller – costing just 1p a tablet – being hailed as ‘the most amazing drug in the world’.
Experts say healthy middle-aged people who start taking low-dose aspirin around the age of 45 or 50 for 20 to 30 years could expect to reap the most benefit, because cancer rates rise with age.
In addition, a 75mg dose – a quarter of a standard 300mg tablet – helps prevent heart attacks and strokes even in people who have not been diagnosed with cardiovascular problems.
Millions of heart patients who already take low-dose aspirin on doctors’ orders to ward off a second heart attack or stroke will be getting built-in cancer protection.
There has been widespread concern that side effects such as stomach bleeding and haemorrhagic stroke would outweigh any advantage among healthy people starting a daily regime.
But Professor Peter Rothwell, of the John Radcliffe Hospital, Oxford, who headed the latest study of almost 26,000 patients, is convinced the ground rules have changed. He said: ‘These findings provide the first proof in man that aspirin reduces deaths due to several common cancers.
‘Previous guidelines have rightly cautioned that in healthy middle-aged people the small risk of bleeding on aspirin partly offsets the benefits from prevention of strokes and heart attacks, but the reductions in deaths due to several common cancers will now alter this balance for many people.’
The study, published in The Lancet medical journal, looked at eight trials where heart patients were allocated daily aspirin or dummy treatment for five years.
The heart benefits had already been reported – this time the researchers wanted to discover what happened to death rates from cancer. They found dramatic results, with aspirin linked to fewer deaths from a host of cancers.
After five years of taking aspirin, death rates fell by 34 per cent for all cancers and 54 per cent for gastrointestinal cancers.
Even after 20 years, the risk of cancer death remained 20 per cent lower in groups previously allocated aspirin for all solid cancers and 35 per cent lower for gastrointestinal cancers.
It took five years for the benefits to emerge for oesophageal (gullet), pancreatic, brain and some forms of lung cancer. It took ten years for protection to take effect in stomach and colorectal cancer and 15 years for prostate cancer.
Too few women were included in the trials to give results for breast and ovarian cancer but the figures were ‘all in the right direction’.
Professor Rothwell, who started taking aspirin two years ago in his mid-40s, said the latest findings underestimated the benefits of taking aspirin over two or three decades.
But he warned it was not possible to predict any ‘unexpected’ effect of taking a drug for a third of a lifetime, so it was up to individuals to weigh up the risks.
Around one person in 1,000 on aspirin might suffer stomach bleeding compared with one in 2,000 to 3,000 non-users, but taking the drug does not result in more fatalities.
Professor Peter Elwood, of the College of Medicine, Cardiff University, who has been investigating aspirin for decades and taking it for 35 years, suggested taking aspirin with a glass of milk at night. He said milk contained calcium which enhanced the drug’s positive effects.
Professor Alastair Watson, of the University of East Anglia, said: ‘This study provides strong evidence that taking regular aspirin for more than five years can help prevent development of a number of other forms of cancer, including lung, pancreas, oesophageal and prostate cancers.
‘It also indicates that the longer aspirin is taken for, the greater the benefit. It is important that people know aspirin can cause dangerous bleeding in the stomach in some patients. People wishing to take aspirin should first discuss it with their GP.’
But, he added, this study ‘is further proof that aspirin is, by a long way, the most amazing drug in the world’.
Nick Henderson, director of the industry-backed Aspirin Foundation, hailed the study as ‘probably the most important news for aspirin since its invention’.
Ed Yong, of Cancer Research UK, said: ‘These promising results build on a large body of evidence suggesting aspirin could reduce the risk of developing or dying from many different types of cancer.’