Wednesday, 19 January 2011

Bowel Cancer and Aspirin

reposted from:
crabsallover highlightskey pointscomments / links.

The potential benefits of Aspirin in preventing cancer have been known about for several years, including as a result of a number of trials and studies. However, the precise dosage required and the duration of treatment needed have not been clear, because of the variability of previous studies.
Until recently, these theoretical benefits were offset by the risk of adverse side effects, such as internal bleeding, caused as a result of the higher dosage of Aspirin (over 300 milligrams) that was believed to be needed to achieve them.
However, recent studies published in the Lancet have shown that a low daily dosage of Aspirin (75 mgs; the same as junior aspirin) taken over a five year period, can reduce longer term (i.e. 20 year) incidence and deaths from the disease, including bowel cancer.

Below, our Chief Medical Advisor, Rob Glynne Jones, answers some questions on Aspirin and cancer:

Who has carried out these studies into Aspirin and cancer?
The studies have been carried out by Professor Rothwell and colleagues at John Radcliffe Hospital, Oxford and other centres. Further studies by the same authors are expected to be published during 2011.
What do these studies show?
They show that a low daily dosage of Aspirin (75 mgs), taken over a five year period, can reduce the long term (i.e. 20 year) incidence of the disease by 24%; deaths from the disease by 35%; and the
odds of developing bowel cancer from one in 28 people to one in 66 people.
Should I start taking Aspirin to help prevent bowel cancer?
Even low dose aspirin has a number of effects on the body, including on normal clotting processes. It would be unwise, therefore, to take aspirin on a regular basis, including as a means of reducing your cancer risk, without discussing it first with your GP.
What are the risks involved in taking Aspirin?
Taking Aspirin increases the risk of developing ulcers in the stomach or gut, which can lead to bleeding. The risk of bleeding increases if the dosage of Aspirin increases, which is why a smaller dosage of 75 mgs is safer than a larger dosage.
Around one in a hundred people are allergic to Aspirin and one in ten people with asthma who take Aspirin find that it makes their asthma worse. As already stated above, Aspirin interferes with the normal clotting process and can make you bleed you more easily.
Is Aspirin a cure for bowel cancer? 
While this news is very exciting and encouraging, Aspirin is not a cure for colorectal cancer and it may help to prevent cancers occurring in only part of the bowel. We would, therefore, strongly encourage people to continue to be vigilant about the disease; to act upon their symptoms and concerns and not ignore them; and, if eligible, to take part in the Bowel Cancer Screening Programme.
What does Aspirin do to help prevent cancer?
We are not entirely sure how Aspirin works in helping to prevent cancer. One theory is that it can reduce persistent inflammation in the body, which is one of the causes of cancer.
What are Aspirin’s other benefits?
Aspirin is best known for being an effective painkiller, which it achieves by blocking a pain generating enzyme in the body called COX-2. Aspirin can also lower the risk of heart disease, strokes and dementia.
What is Bowel Cancer UK’s response to the studies?
We welcome these studies. It is encouraging that a lower dosage of Aspirin, and one with a reduced risk of side effects, appears to have such a positive effect on preventing bowel cancer. We look forward to the results of future studies refining our understanding of this process.
Is age a factor in people benefitting from Aspirin?
While Aspirin benefits people of all ages, it appears to have the greatest impact in people aged over 65, in the main because older people have an increased risk of cancer related death. As the statistics show, Aspirin reduces the risk of dying from cancer by 7% for people over 65; and by 3.5% for all the people in the trials combined.
What about longer term treatment with Aspirin?
The authors of the study believe that if people are treated with lower dose aspirin for 20 to 30 years, those who start to do so in their late 40s or 50s are the most likely to benefit longer term. They also say that the risk of death from bowel cancer is reduced by about 40% if people take Aspirin over 20 years.
Does Aspirin prevent tumours in all areas of the bowel? 
While Aspirin might help prevent tumours in all areas of the bowel (e.g. in the colon and the rectum),the evidence suggests that it is most effective in preventing tumours in the first part of the bowel, i.e. in the ascending and transverse colon.
Reference: Rothwell, P., Fowkes, F., Belch, J., Ogawa, H., Warlow, C., & Meade, T. (2010). Effect of daily aspirin on long-term risk of death due to cancer: analysis of individual patient data from randomised trials The Lancet DOI: 10.1016/S0140-6736(10)62110-1
Last updated 17th January 2011

No comments: