Can Aspirin Really Prevent Cancer?
A new study adds weight to the argument for a daily aspirin to ward off cancer, although the efficacious effects are not as great as often claimed. This is by no means the last word on the popular but misunderstood drug by the experts. Because just as in previous research the new study has important riders.
The advice from doctors in America is for patients to take aspirin in small quantities as long as the side effects are not too bad. Aspirin helps to prevent heart disease, but is purely preventive and should not be taken by patients who have already had heart problems. Whether this advice should be extended to cover cancer is still not finalized.
Aspirin and Cancer Risk
Early in 2012 there was a meta-analysis of all the test data on aspirin. It revealed that patients treated with it were less prone to death from cancer than patients not taking the drug. Overall there was a 37% improvement in mortality rates seen from 5 years and onwards. This latest study, published late last week in the Journal of the National Cancer Institute, was made from clinical observations rather than laboratory trials. It included 10 years’ worth of results from over 100,000 older (60 plus) male and female, non-smoking Americans.
[box type="note"]The patients who reported taking daily aspirin regardless of the dosage strength had a 16% lower risk of death from cancer than those who never took the drug. The males in the study had 103 fewer annual deaths from cancer while for the females the lowered risk meant 42 fewer deaths.[/box]
Gastrointestinal Cancer Risk
The cancer prevention effect was best for gastrointestinal cancers such as cancer of the colon or stomach. There was little correlation between the length of time for which Aspirin was used as long as it was for 5 years at least. The biggest question mark over hanging the study comes from it not being an experimental study. Was there some other factor at play in causing the results?
The authors of the study do however recommend the extension of aspirin guidelines to cover cancer prevention as long as the individual patients have a proper risk versus benefit assessment. Other experts in the field are not being so quick to push the aspirin bandwagon because of the potential adverse side effects such as stomach bleeding and the fact that the study did not include overall death rates in their analysis.
Another meta-analysis of aspirin studies published earlier this year came out with contradictory results; aspirin was not shown to prevent even heart disease but was a risk for harmful side effects.
Many aspirin studies and meta studies are prone to ‘detection bias’. When the aspirin causes stomach bleeds patients are more frequently checked by doctors and this leads to abnormally high, early detection rates of bowel and stomach cancers. This in turn leads to operations for the removal of cancerous tumors and explains at least some of the better mortality figures. Watch this space for further news on cancer prevention trials.