The little white pill that became a wonder drug

Aspirin used to be considered a mere painkiller, but research now shows that the cheap drug can play a major part in preventing deaths from various forms of cancer – just the latest discovery about its wide-ranging health benefits

THE NEWS THIS week that the humble aspirin tablet can help reduce deaths from a broad range of cancers is hugely significant. Although it has, like every drug, potential side effects, it now seems likely that reservations about the risk of serious bleeding from the gut will be outweighed by the many cardiovascular and cancer benefits of aspirin. So should we all be popping an aspirin with our cornflakes every morning?

What is aspirin?Aspirin, also known as acetylsalicylic acid, is a drug that has been used since the early 1900s. It has an anti-inflammatory action, and is used as a painkiller. It costs a couple of cents a tablet.

How does it work?At a cellular level it blocks the action of an enzyme called cyclooxygenase, which is involved in the production of prostaglandins, chemicals that promote inflammation in various parts of the body. For a number of years, people with a history of stroke or heart attack and those at high risk of having a serious cardiovascular event have been prescribed 75mg of aspirin daily to help prevent blood clots forming in blood vessels. Specifically, it stops platelets in the blood sticking together to form a clot and helps people avoid recurrent heart attacks.

What is the evidence that it can prevent the progression of cancer?Researchers at Oxford University found that taking aspirin reduced overall cancer mortality by a fifth. The reduction was across a broad range of cancers. The 20-year risk of death was reduced by about 10 per cent for prostate cancer, 30 per cent for lung cancer, 40 per cent for colorectal cancer and 60 per cent for oesophageal (gullet) cancer. Benefits were seen after taking aspirin for five years for oesophageal, pancreatic, brain and lung cancer. Taking aspirin for 10 years reduced death from stomach cancer, while mortality from prostate cancer dropped after taking aspirin for some 15 years.

How is aspirin achieving these reductions?Researchers are not absolutely certain about this, but the lead author of this week's landmark study, Prof Peter Rothwell, said laboratory tests suggested aspirin intervenes at an early stage. Cancers occur when cells divide abnormally. The body has a mechanism whereby either the faulty cells kill themselves (a process called apoptosis) or they self-repair. Aspirin seems to work either by enhancing cell suicide or by improving the repair. Inflammation also plays a central role in cancer development. It seems the inflammatory process switches on factors that encourage the growth of new blood vessels in cancerous tissue. The anti-cyclooxygenase action of aspirin comes into play here.

Can aspirin be given to children?No. Aspirin can rarely cause Reye's syndrome in children, which may lead to serious brain and liver inflammation. Aspirin may also cause a flare-up of pre-existing asthma.

What about the risks of unwanted bleeding in people taking aspirin?There is a small but definite risk that aspirin can cause bleeding, especially in the gut. If you have had a gastric or duodenal ulcer in the past, then the risk of a bleed from the stomach is higher. For every 850 or so patients treated with aspirin for a year, one person will experience a major gastrointestinal bleed. Aspirin is estimated to cause one additional brain haemorrhage for every 3,300 people who take the drug for a year.

So should people of a certain age go out and buy low-dose aspirin based on the latest research?No, they should not. Before starting aspirin, you should visit your GP; in particular, you need your personal risk benefit calculated and explained to you. If there are no reasons why you should not take aspirin, then experts suggest that taking 75mg at night with a glass of milk from the age of 45 or 50 until the age of 70 or 75 will provide the maximum benefit in terms of reducing the risk of dying from certain cancers.

Can you summarise the health benefits of aspirin?The range of benefits attributable to aspirin continue to grow, leading some to label it a "superdrug" this week. As well as lowering deaths from a range of common "solid" cancers, aspirin saves lives in those with established cardiovascular disease. There is some evidence aspirin may help to prevent dementia, which would certainly make sense in cases where the dementia was the result of a series of mini-strokes. And of course it remains a good treatment for fever in adults, as well as an effective anti-inflammatory drug for people with arthritis.