A study which found that a daily dose of aspirin cuts the incidence of bowel cancer, “provides the strongest evidence yet” that the drug could reduce the risk of developing colon cancer, according to Maltese oncologist Stephen Brincat.
“It has been known that aspirin taken over a period of years can reduce the risk of developing colon cancer for some time. This study provides the strongest evidence yet,” Dr Brincat, consultant clinical chairman of the Oncology Department at Sir Paul Boffa hospital said.
The study, published in reputable medical journal The Lancet, tackled the long-term effect of aspirin on cancer risk in carriers of hereditary colorectal cancer. It said two pills a day for two years reduced the incidence of bowel cancer by 63 per cent in a group of 861 at-risk patients.
In 2009, a British Journal of Cancer study suggested aspirin could cut the risk of a type of stomach cancer by a third and research at Oxford University and other centres showed it cut overall cancer deaths by at least a fifth.
Some experts have, however, insisted that aspirin consumption could actually increase the risk of getting a stroke, among other negative side effects, including peptic ulceration and gastrointestinal bleeding.
Newcastle University professor John Burn, who led the study published online yesterday, said: “If all the people in the UK who carry Lynch syndrome could be identified and were started on two aspirins a day we would prevent about 10,000 cancers over the next three decades but we would cause about 1,000 ulcers.”
He said that, although bleeding from the gut could be serious, it was rarely fatal and the use of acid blockers could reduce the problems.
“Aspirin will also reduce heart attacks and strokes but there is a small additional risk of cerebral bleeds, which are rare but serious. In the general population, the combined benefit of reduced risk of cancer, heart disease and strokes will be seen by many as sufficient grounds to take the chance of getting an ulcer,” he said.
“What we have shown is that the balance is clearly in favour of using aspirin if you have a strong family history of cancer, especially if it is cancer of the bowel,” Prof. Burn said.
He added that he personally took a 75mg aspirin each day because he felt the “benefits outweigh the risk”.
Dr Brincat explained that the study tested the theory on patients with a strong family history who were at a particularly high risk of developing colorectal cancer at an early age and where the progression from pre-cancerous to cancer could be expected to develop faster.
He said such patients derived the same degree of benefit as seen with screening but one could not substitute the other. The optimum dose and time for which aspirin should be taken were still unknown.
Dr Brincat said the potential side effects of aspirin were peptic ulcers and increased risk of bleeding.
“Our department was considering joining a study exploring the use of another anti-inflammatory drug in colorectal cancer prevention but the study was stopped because of concern about the cardiac risks of this drug. There seems to be no such concern with aspirin and it’s certainly something to be considered in patients with the necessary criteria of risk,” he said.
Consultant physician Charles Mallia Azzopardi reiterated that numerous studies had shown a link between long-term, high dose aspirin with reduced incidence of cancerous colonic polyps.
“However, aspirin, especially high dose aspirin, comes with its own side effects such as gastrointestinal bleeding, which can be severe,” he added.
Dr Mallia Azzopardi said that although the studies were promising one could not yet prescribe aspirin to the population to decrease the incidence of colonic cancer. “Further studies are needed to establish the optimal dose and duration of aspirin treatment,” he said.