Taking a daily dose of aspirin could cut bowel cancer patients’ chance of dying from the disease by about a third, say experts.

The study published in the British Journal of Cancer looked at 4,500 bowel cancer patients living in The Netherlands.

All of the patients on aspirin were taking a low dose – 80 mg or less a day – something already recommended for people with heart disease.

But experts say it is too soon to start routinely offering it for bowel cancer.

A wealth of evidence already suggests aspirin might prevent certain cancers from developing in the first place. And more recent work suggests it might also work as a cancer therapy – slowing down or preventing a cancer’s spread.

But the drug can also have unpleasant and dangerous side effects, causing irritation of the stomach lining and internal bleeds in a very small minority of patients.

In the study, which spanned nearly a decade, a quarter of the patients did not use aspirin, a quarter only took aspirin after being diagnosed with bowel cancer, and the remaining half took aspirin both before and after their diagnosis.

Most of the patients on aspirin had been taking it to prevent cardiovascular disease-related problems like stroke or heart attack.

Taking a daily dose of aspirin could cut bowel cancer patients’ chance of dying from the disease by about a third

Taking aspirin for any length of time after diagnosis cut the chance of dying from bowel cancer by 23%.

The patients who took a daily dose of aspirin for at least nine months after their diagnosis cut their chance of dying from the disease by 30%.

Taking aspirin only after bowel cancer had been detected had a bigger impact on reducing mortality compared with when aspirin was taken before and after diagnosis – reducing death risk by 12%.

This may be because those who took aspirin and still got bowel cancer had a particularly aggressive form of tumor that did not respond as well to aspirin, say the researchers.

Lead researcher Dr. Gerrit-Jan Liefers, of the Leiden University Medical Centre, said: “Our work adds to growing evidence that aspirin not only can prevent cancer from occurring but if it is there it can help prevent it spreading.”

He said aspirin should not be seen as an alternative to other treatments, such as chemotherapy, but could be a useful additional treatment.

“It’s possible that some older people may have other health problems which mean that they are not well enough to have chemotherapy. Bowel cancer is more common in older people so these results could be a big advance in treatment of the disease, particularly in this group. But we need further research to confirm this.”

Dr. Gerrit-Jan Liefers said they now planned to hold a randomized controlled trial – the “gold standard” in medical research – to look at how well aspirin fared against a dummy drug in people aged over 70 with bowel cancer.

Aspirin

• Active ingredient is acetylsalicylic acid

• Used for many years as a painkiller

• Has an anti-inflammatory action

• Low-dose (75 mg) is already recommended for people with known cardiovascular disease to prevent stroke and heart attack

• Benefits for healthy people are still unclear

• Can cause fatal internal bleeding, although this is relatively rare