For several years it has been thought that aspirin might be a powerful way of reducing our risk of cancer, particularly bowel cancer. This month important new evidence has emerged.
The bad news is that taking low doses of aspirin every day — ie, the dose taken by many thousands of people to help prevent heart attacks — does not seem to have any effect on bowel cancer risk.*
The good news is only for people with an inherited high risk of bowel cancer. For these people taking a daily high dose of aspirin can lower the risk dramatically (by 63 per cent if taken for two years). And the latest results show the effect is particularly strong among obese people.
The problem is the side effects of these higher doses of aspirin (that is, the amount used as a painkiller). For some they can cause internal bleeding and life-threatening allergic reactions. So they are only worth taking if you know you have an inherited high risk of bowel cancer — specifically, if you are likely to have Lynch syndrome.
* The Times has in fact reported the opposite: that a daily low dose can reduce bowel cancer risk. But Professor Matt Seymour, Cancer Research UK’s bowel cancer specialist, says the evidence does not support this claim. The study, to be published in the Annals of Internal Medicine this week, found that taking a daily dose of 75mg to 150mg of aspirin for anything less than five years had no impact on cancer risk. And though it appeared to have an impact for people who took aspirin continuously for longer than five years, only 45 out of the 113,000 individuals looked at in the study fit this category. So the data cannot be used to prove a link. Aspirin, says Professor Seymour, has not yet been proven as the ‘magic pill’.
The study, also reported by Reuters, showed a much stronger link between a reduction of bowel cancer risk and non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen. But these drugs, unlike aspirin, have no positive impact on your risk of cardiovascular disease — in fact they will probably make a heart attack more likely.