Aspirin may protect against breast cancer and assist treatment
Anti-inflammatory drugs such as aspirin may reduce the incidence of breast cancer by up to 20 per cent and also benefit patients who already have the disease, new research has found.
But the study did not account for side-effects, and a Cancer Research UK spokesperson warned that people should not take aspirin in large doses, or for long periods of time, without proper medical advice.
Aspirin belongs to a class of drugs called non-steroidal anti-inflammatory drugs (NSAIDs) which are good at relieving bone and muscle pain.
Published in the International Journal of Clinical Practice (IJCP), the extensive review by scientists at London's Guy's Hospital looked at 21 studies involving more than 37,000 women between 1980 and 2007.
Eleven of the studies involved women with breast cancer, while the remaining ten studies compared women who had the disease with women who were cancer-free.
Professor Ian Fentiman, who carried out the review alongside Avi Agrawal, revealed: "Having weighed up the findings from over 20 studies, we have concluded that NSAIDs may well offer significant protection against developing breast cancer in the first place and may provide a useful addition to the treatment currently available to women who already have the disease.
"Recent studies of NSAIDs use have shown about a 20 per cent risk reduction in the incidence of breast cancer, but this benefit may be confined to aspirin use alone and not other NSAIDs.
"NSAID use could be combined with hormone therapy or used to relieve symptoms in the commonest cause of cancer-related deaths in women."
The reviewers noted that further research will be needed to determine the best type, dose and duration of aspirin treatment, and whether the benefits of taking aspirin outweigh the side-effects.
Professor Fentiman, from the hospital's Hedley Atkins Breast Unit, noted that the review did not look at side-effects, which can include gastrointestinal bleeding and tears in the lining of the gut wall.
"It would be essential to take these negative effects into account before we could justify routinely using NSAIDs like aspirin to prevent breast cancer. More research is clearly needed and we are not advocating that women take these non-prescription drugs routinely until the benefits and risks are clearer," he noted.
"But our findings clearly indicate that these popular over-the-counter drugs could, if used correctly, play an important role in preventing and treating breast cancer."
Dr Kat Arney, Cancer Research UK's senior cancer information officer, said: "Drugs like aspirin are often touted as 'wonder-drugs' and we have seen repeatedly from studies like this that there can be a range of positive effects.
"But, as with any drug there can be significant side-effects from long term or heavy use - such as stomach ulcers - so we certainly wouldn't recommend that people take large doses without medical advice. More research is needed to investigate how the side-effects can be balanced with the benefits of these drugs."
Previous studies have suggested that aspirin may also provide some protection against bowel cancer.