A US study has found that a daily dose of aspirin may reduce the risk of prostate cancer, but Cancer Research UK has noted that regular use of aspirin can cause serious side-effects and should not be undertaken unless recommended by a doctor.

Several previous studies have looked at the possibility of an association between aspirin use and a reduced risk of prostate cancer.

In the latest study, scientists at the Fred Hutchinson Cancer Research Centre in Seattle, led by Dr Janet Stanford, looked at data on 1,001 prostate cancer patients and a similar number of cancer-free volunteers.

They discovered that men who took a low daily dose of aspirin - which has anti-inflammatory properties - were 29 per cent less likely to be diagnosed with prostate cancer than those who did not.

However, no such association was found for other non-steroidal anti-inflammatory drugs, such as ibuprofen.

Publishing their findings in the American Journal of Epidemiology, the study authors said: "The significant inverse association between prostate cancer risk and use of aspirin that we observed provides additional support for the role of inflammation in the development of this cancer.

"If aspirin delays the onset or progression of prostate cancer through its anti-inflammatory activities, this may offer another agent to be tested in prevention trials."

However, Dr Claire Knight, Cancer Research UK's health information officer, urged caution.

She said: "Many other studies have looked for links between aspirin and prostate cancer but the overall picture is inconsistent and this small study doesn't add much clarity to it.

"Regularly taking aspirin can have serious side-effects, including bleeding from the gut, and so larger clinical trials are needed to tell us whether the possible benefits of aspirin outweigh the risks.

"It's important that any decision to take aspirin regularly is only made in consultation with a doctor."