Should You Be Taking Aspirin?
In August 2014 a scientific study published in the Annals of Oncology received huge publicity. The study examined the effect of aspirin in preventing cancer. Interest in aspirin as a drug to prevent cancer began to emerge in 2012 when two major studies (here and here), that were actually looking into the effectiveness of aspirin in reducing heart disease, demonstrated that people taking regular aspirin had a reduction in both cancer occurrence and death from cancer.
The researchers in this later study collated results from over 200 different scientific studies and examined the potential benefits and harms of taking aspirin. The study focused on people aged over 50. They discovered that protection against cancer became evident after taking aspirin for 3 years and a protective effect against dying of cancer after 5 years.
The results of the study show that if 1,000 people aged 60 were to take aspirin every day for 10 years, by the time those people were 80 there would have been:
16 fewer deaths from cancer
1 less death from a heart attack, but
2 extra deaths due to bleeding caused by aspirin
To put it another way 63 people have to take aspirin every day for ten years to prevent one death from cancer. For every 500 people who take aspirin every day for ten years one person will die due to bleeding caused by the aspirin.
The study showed that the greatest benefit was in preventing cancers of the colon and rectum. For each individual the benefits and potential harms should be carefully weighted up. We know, for example, that the common stomach bacteria helicobacter pylori doubles the risk of bleeding due to aspirin. So if you are thinking of starting aspirin to prevent cancer it would be worth having a test for helicobacter first. The people who are most likely to benefit from taking aspirin are those who have a low risk of bleeding but have a relatively high risk for developing cancers and in particular, colon cancer.
As is the case in most areas of medicine, the decision as to whether to start aspirin should be unique to that individual. People over 50 who have a high risk of cancer, from family history for example, would certainly benefit from speaking to their doctor to find out whether a daily aspirin may be suitable for them.
Dr Hugh Coyne