No Easy Answers about Whether Aspirin Lowers Cancer Risk
One of the most intriguing prospects in cancer prevention is a cheap and very familiar drug: aspirin. Later this year, in fact, the U.S. Preventive Services Task Force Exit Disclaimer is expected to release recommendations on the use of aspirin to reduce cancer risk.

Aspirin is already widely used. Tens of millions of people in the United States take it daily to reduce their risk of heart attack or stroke. And numerous studies over the last two decades have suggested that taking aspirin on a regular basis may substantially lower a person’s risk of developing or dying from cancer.

In 2011, for example, a meta-analysis of eight randomized clinical trials that compared the risk of cancer death among participants who took daily aspirin for 4 years or more and those who took no aspirin found that, overall, aspirin use lowered the risk of dying from cancer by approximately 20 percent.

By looking at data from individual participants in these trials, the researchers, led by Peter Rothwell, MD, PhD, FRCP, of the University of Oxford, showed that this risk reduction was due mainly to fewer cancer deaths among participants who took aspirin for at least 5 years. The largest drop in risk was for gastrointestinal cancers, particularly colorectal cancer. The study also showed more modest risk reductions for several other common cancers, including lung and prostate.

The research findings on aspirin, however, are not clear cut. Not every study of aspirin and cancer has shown that it reduces the risk of developing or dying from cancer. And most of the research linking aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) and a lower risk of developing or dying from cancer have had limitations; most have been either observational studies, which cannot establish causal effect, or analyses of clinical trials testing aspirin’s effect on other health measures, most often vascular outcomes. None of the trials included in the 2011 meta-analysis, for example, was designed specifically to assess whether aspirin reduces the rate of cancer or cancer deaths.

Aspirin may reduce cancer risk
People may soon be advised to take a regular dose of aspirin in a bid to stave off cancer, heart disease and even senile dementia.

Doctors believe there could be enough medical evidence in the next 10 years to support widespread use of the drug.

But they are also calling for more research on the extent of aspirin’s known side-effects and warned patients not to self-prescribe.

A London conference on the uses of aspirin in preventing cancer heard there was increasing evidence of the drug’s beneficial effect across a range of diseases.

It is already known to cut the risk of heart attacks and strokes in high-risk patients by up to a third.

There is also evidence to suggest that it could help prevent breast, prostate and bowel cancers, which claim up to 17,000 lives a year. Professor Peter Elwood, the doctor who first discovered the benefits of aspirin in treating cardiovascular disease, told The Times: “There’s already abundant evidence of aspirin’s profound advantages to cardiovascular disease, a possible reduction of Alzheimer’s and probable reduction in a number of cancers.

“Should everyone over 50 or 55 or 60 be advised to take aspirin every day? It is a very serious question that needs to be asked and I believe we should debate that question.î But aspirin can occasionally-cause internal bleeding and even ruptured blood vessels in people with ulcers and weak stomach linings.

Pregnant women are also at risk because it can increase the risk of a miscarriage.

A recent study of 1,000 people who were at increased risk of bowel cancer found that those taking aspirin reduced the threat of developing pre-cancerous growths by 19 per cent. Trials are ongoing but initial results are said to be equally positive.

A further study carried of 80,000 women found that those who regularly used drugs such as aspirin and ibuprofen had the risk of developing breast cancer cut by almost 30 per cent in comparison with those who did not.