A daily dose of aspirin has been found to significantly cut the risk of developing and dying from a number of cancers in the digestive tract.

According to a review of evidence by researchers at Queen Mary University of London*, taking aspirin for 10 years could cut bowel cancer cases by 35% and oesophageal and stomach cancers by 30%. 

Deaths from these cancers were slashed by 40% and 35%-50%, respectively.

To attain this benefit, people aged between 50 and 65 years should start taking a daily dose of 75mg-100 mg for at least five years and probably for 10 years, the evidence shows.

Bleeding and ulcers

On the down side, taking aspirin long-term does raise the risk of bleeding from the digestive tract and developing peptic ulcers, but the research shows that, at face value, the pros still outweigh the cons.

Overall, rates of serious or fatal gastrointestinal bleeding are very low under the age of 70, but increase sharply after that age, the researchers said, while the chances of developing peptic ulcers leapt 30%-60%.

The data suggest that, if 1,000 sixty year-olds took daily aspirin for 10 years, within 20 years there would be around 16 fewer cancer deaths but two extra from bleeding.

"Whilst there are some serious side effects that can’t be ignored, taking aspirin daily looks to be the most important thing we can do to reduce cancer after stopping smoking and reducing obesity, and will probably be much easier to implement,” commented Jack Cuzick, Queen Mary University of London.

"Our study shows that if everyone aged between 50-65 started taking aspirin daily for at least 10 years, there would be a 9% reduction in the number of cancers, strokes and heart attacks overall in men and around 7% in women. The total number of deaths from any cause would also be lower, by about 4% over a 20-year period,” he said.

Varied picture

However, a CR UK blog points out that the picture is complicated by the fact that the risks and benefits don’t apply equally across the population. Some people will be at higher risk of side effects, while for others, those who wouldn’t have developed cancer anyway, the benefits are lower.

To ensure maximum benefit and lowest risk, doctors need to know what age should people start and stop taking aspirin, what the dose should be, and the factors ruling someone out from this preventative strategy. 

“At the moment, frustratingly, there’s no clear, definitive answer to these questions. And until there are, we’re emphatically discouraging people from stocking up on their own supplies of aspirin without seeking medical advice first,” the charity stressed.

*Part funded by Cancer Research UK and published in the Annals of Oncology