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But four in five oncologists interviewed said more research has to be done to weigh the benefits of the routine use of aspirin against possible side effects. JOAN CHEW reports
 A daily low dose of aspirin could reduce the risk of dying from cancer, according to a new study published in the online edition of the medical journal, The Lancet, last week. It would be such an easy and inexpensive way of keeping cancer at bay that one of the study’s researchers suggested healthy people should start taking 75mg of aspirin daily, till they get to their 70s. But four out of five oncologistsinterviewed by Mind Your Body urged caution because of the propensity of aspirin to cause bleeds in the gastrointestinal tract and brain. They said they could not recommend the routine use of aspirin in the general population until more work has been done to weigh its benefits against its potential side effects.
The study was a review of eight trials involving 25,570 patients over several years and was aimed at determining the role of aspirin in cardiovascular diseases such as heart attacks and stroke. However, researchers from the University of Oxford also found that cancer deaths among those who took aspirin in doses as low as 75mg a day were 21 per cent lower during the studies and 34 per cent lower after five years. The 20-year risk of death went down 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 cancer in those taking aspirin. Too few women were in the review to ascertain the effect of aspirin against gynaecological cancer.
 Aspirin belongs to a class of drugs called non-steroidal anti-inflammatory drugs that reduce inflammation in the body. For relief of fever and pain such as headache, it is usually taken at doses of 325 to 1,000mg. A daily dose of more than 500mg of aspirin is associated with the highest risk of stomach ulcer and bleeding, the most dangerous side effects from aspirin use. But the side effects are greatly lessened at doses of 75mg, which is the amount taken daily by many heart patients to reduce therisk of blood clots. The use of aspirin and other anti-inflammatory medication for cancer prevention has long been a subject of research, said Dr See Hui Ti, medical oncologist at Parkway Cancer Centre. She said: “Clinical trials have long proven that the use of aspirin reduces the stickiness of blood, leading to a reduction in the risks of strokes and heart attacks.”
Dr See said it is known that patients who have been on aspirin for more than 10 years have a reduced risk of colorectal cancer. This is because aspirin reduces inflammation in the gut which result in pre-cancerous polyps. These are non-cancerous growths that develop from the cells lining the inside of the colon or rectum, which tend to become cancerous over a long time, she said. However, the Lancet study was not intended to and did not show if aspirin reduced the number of polyps, said Dr Peter Ang, consultant medical oncologist at the OncoCare Cancer Centre.
In fact, the study did not show if aspirin could prevent someone from getting cancer altogether, noted Dr Wong Seng Weng, consultant and medical director of The Cancer Centre. What it showed was areduced chance of dying from it. According to the Singapore Cancer Registry, colorectal cancer is the most common cancer among men, at 46.9 per 100,000 each year. But it has only the second highest mortality rate, after lung cancer, at 20.1 per 100,000 per year. The Oxford study did not show if cancer incidence was reduced after patients went on aspirin.
Dr Benjamin Chuah, consultant from the department of haematology-oncology at the National University Cancer Institute, Singapore, said: “The trials were not designed to study cancer specifically, but were originally designed to examine the role of aspirin in vascular diseases such as stroke and heart disease. “Thus, we cannot tell what population of patients to target for aspirin use, the optimal duration of therapy and at what age treatment should be started." One of the researchers, Professor Peter Rothwell, suggested that healthy people can start taking a small 75mg dose of aspirin every day from the age of about 40 or 45 and continue doing so until they reached around 70 to 75 years old. This is when the risk of the aspirin causing stomach bleeding rises. Dr See agreed that anyone seeking to reduce their colorectal cancer risk can consider taking aspirin daily for more than 10 years, but must consult their doctor first. She said these people would still need to be screened for colorectal cancer every five to 10 years.
Dr John Chia, consultant from the department of medical oncology at theNational Cancer Centre, Singapore, hailed the study as “an important piece in the amazing aspirin story”. However, for it to change the clinical practice of doctors worldwide, he said that they need to be convinced, beyond doubt, that treating healthy individuals with aspirin will yield more benefits than harm. He said: “Most doctors would find that prescribing aspirin to thousands of healthy people for 20 years, in order to prevent a handful of cancer deaths, may not be worthwhile. “This is especially so if the number of people who benefit is roughly the same as those who experience side effects from aspirin.”
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