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Aspirin: Scientists believe cancer prevention benefits outweigh harms

Date:
August 5, 2014
Source:
Oxford University Press (OUP)
Summary:
Taking aspirin can significantly reduce the risk of developing – and dying from – the major cancers of the digestive tract, i.e. bowel, stomach and oesophageal cancer, researchers report. For the first time, scientists have reviewed all the available evidence from many studies and clinical trials assessing both the benefits and harms of preventive use of aspirin.
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New research from Queen Mary University of London (QMUL) reveals taking aspirin can significantly reduce the risk of developing -- and dying from -- the major cancers of the digestive tract, i.e. bowel, stomach and esophageal cancer.

For the first time, scientists have reviewed all the available evidence from many studies and clinical trials assessing both the benefits and harms of preventive use of aspirin. Conclusions of the study are published in the leading cancer journal Annals of Oncology.

The researchers, led by Professor Jack Cuzick, Head of the Centre for Cancer Prevention at QMUL (London, UK), found taking aspirin for 10 years could cut bowel cancer cases by around 35% and deaths by 40%. Rates of esophageal and stomach cancers were cut by 30% and deaths from these cancers by 35-50%.

To reap the benefits of aspirin, the evidence shows people need to start taking a daily dose of 75-100 mg for at least five years and probably 10 years between the ages of 50 and 65. No benefit was seen whilst taking aspirin for the first three years, and death rates were only reduced after five years.

However, the research also warns taking aspirin long-term increases the risk of bleeding from the digestive tract, e.g. stomach bleeding. Amongst 60-year-old individuals who take daily aspirin for 10 years, the risk of digestive tract bleeds increases from 2.2% to 3.6%, and this could be life-threatening in a very small proportion (less than 5%) of people.

Overall, rates of serious or fatal gastrointestinal bleeding are very low under the age of 70, but increased sharply after that age. Another side effect of aspirin use is peptic ulcer, the risk of which is increased by 30-60%.

The study also uncovers uncertainty over the most appropriate dose of aspirin required to maximize the benefit / harm ratio, with doses varying between 75 mg to 325mg a day in different clinical trials and studies. It is also not clear whether taking aspirin for longer than 10 years will result in greater benefits.

Professor Jack Cuzick commented: "It has long been known that aspirin -- one of the cheapest and most common drugs on the market -- can protect against certain types of cancer. But until our study, where we analysed all the available evidence, it was unclear whether the pros of taking aspirin outweighed the cons.

"Whilst there are some serious side effects that can't be ignored, taking aspirin daily looks to be the most important thing we can do to reduce cancer after stopping smoking and reducing obesity, and will probably be much easier to implement."

"Our study shows that if everyone aged between 50-65 started taking aspirin daily for at least 10 years, there would be a 9% reduction in the number of cancers, strokes and heart attacks overall in men and around 7% in women. The total number of deaths from any cause would also be lower, by about 4% over a 20-year period. The benefits of aspirin use would be most visible in the reduction in deaths due to cancer.

"The risk of bleeding depends on a number of known factors which people need to be aware of before starting regular aspirin and it would be advisable to consult with a doctor before embarking on daily medication."

Further research is needed to define more clearly who will benefit most greatly from taking aspirin and who is most at risk of the bleeding side effects.


Story Source:

The above post is reprinted from materials provided by Oxford University Press (OUP). Note: Materials may be edited for content and length.


Journal Reference:

  1. J. Cuzick, M. A. Thorat, C. Bosetti, P. H. Brown, J. Burn, N. R. Cook, L. G. Ford, E. J. Jacobs, J. A. Jankowski, C. La Vecchia, M. Law, F. Meyskens, P. M. Rothwell, H. J. Senn, A. Umar. Estimates of benefits and harms of prophylactic use of aspirin in the general population. Annals of Oncology, 2014; DOI: 10.1093/annonc/mdu225

Cite This Page:

Oxford University Press (OUP). "Aspirin: Scientists believe cancer prevention benefits outweigh harms." ScienceDaily. ScienceDaily, 5 August 2014. <www.sciencedaily.com/releases/2014/08/140805221119.htm>.
Oxford University Press (OUP). (2014, August 5). Aspirin: Scientists believe cancer prevention benefits outweigh harms. ScienceDaily. Retrieved July 31, 2015 from www.sciencedaily.com/releases/2014/08/140805221119.htm
Oxford University Press (OUP). "Aspirin: Scientists believe cancer prevention benefits outweigh harms." ScienceDaily. www.sciencedaily.com/releases/2014/08/140805221119.htm (accessed July 31, 2015).

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