Long-Term Aspirin Lowers Hereditary Cancer Risk By Over 60%

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Main Category: Cancer / Oncology
Article Date: 28 Oct 2011 - 0:00 PDT

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Patients with a family history of cancer who take daily aspirin for a number of years have a 63% lower chance of developing the disease, scientists from the Universities of Newcastle and Leeds, England, reported in the medical journal The Lancet. The researchers emphasized that it takes some years of daily aspirin therapy for the benefits to kick in.

The authors explained that over the last two decades there has been growing evidence of a cancer-protecting quality in aspirin. However, this is the first proper randomized controlled study to look at aspirin's effect on cancer risk.

A study that looked at aspirin's preventive benefits against heart attack and stroke eventually showed that participants had a much lower risk of developing cancer.

Team leader, Professor Sir John Burn said:

"What we have finally shown is that aspirin has a major preventative effect on cancer but this doesn't become apparent until years later."

The study tracked nearly 1,000 patients from 43 centers in 16 different countries. Some of them were followed for over ten years.

The trial concentrated on individuals with Lynch syndrome. Lynch syndrome is a rare, inherited condition that raises the person's risk of developing colon cancer, as well as other cancers, such as cancer of the skin, brain, upper urinary tract, uterus, hepatobiliary tract, small intestine, stomach, ovary, and endometrium. The higher risk of cancer is caused by inherited mutations that undermine DNA mismatch repair. Approximately half of all people with Lynch syndrome develop cancer, usually of the womb or bowel.

861 individuals took either two aspirins (600mg) daily for two years or a placebo - they started between 1999 and 2005. By 2007 there was no difference in cancer risk between the two groups. However, the researchers continued monitoring the patients.

By 2010 they detected 34 new cases of colorectal cancer in the placebo group, compared to 19 in the aspirin group. Cancer incidence had more than halved in the aspirin group. It took time for any beneficial effect to be noticed.

A Newcastle University communiqué informed:

"A further analysis focused on the patients who took aspirin for at least two years according to the original design - some 60% of the total - and here the effects of aspirin were even more pronounced: a 63% reduced incidence of colorectal cancer was observed with 23 bowel cancers in the placebo group but only 10 in the aspirin group."

15% in the aspirin group developed some kind of cancer related to Lynch syndrome, compared to nearly 30% in the placebo group.

Co-author, Professor Tim Bishop, said:

"What surprised us was that there was no difference in the number of people developing polyps which are thought to be the precursors of cancer. But, many fewer patients who had been taking aspirin years before went on to develop cancers."

Sir John said:

"We have succeeded in showing the benefits of aspirin because we had a lot of long term data and because Lynch syndrome is associated with rapid development of cancer.

It has also demonstrated how our research community and families with inherited forms of cancer can work together to answer questions important for the whole population.

Before anyone begins to take aspirin on a regular basis they should consult their doctor as aspirin is known to bring with it a risk of stomach complaints including ulcers.

However, if there is a strong family history of cancer then people may want to weigh up the cost-benefits particularly as these days drugs which block acid production in the stomach are available over the counter."

Director of the Medical Research Council Human Genetics Unit, Professor Nick Hastie, said:

"Bowel cancer is the second commonest cause of cancer death in the UK, being responsible for 16,000 deaths a year. This landmark study provides the clearest evidence yet that aspirin can help protect against development of this disease. As we learn more about the underlying mechanism of this anti-tumour effect, we will eventually be able to develop new ways of preventing and treating cancer."

The investigating team, which includes people from various countries, say they are planning a large-scale follow-up study, hopefully with at least 3,000 people from around the world. The aim is to try out different aspirin dosages. Two aspirins per day will be compared to smaller amounts.

How does aspirin do protect from cancer?

Some mechanism which predisposes an individual to cancer is being affected by cancer, the scientists believe. They say further studies are needed before they can be sure what it is.

The effect must be occurring in cells before they eventually become predisposed to cancer, because the aspirin prevents even the early stages of developing a tumor from occurring (adenoma carcinoma sequence).

Perhaps aspirin encourages programmed cell death. This occurs in plants, where salicylates help stem the spread of a disease. Aspirin, also known as acetylsalicylic acid, is a salicylate drug.

Sir John said:

"We may be seeing a mechanism in humans whereby aspirin is encouraging genetically damaged stem cells to undergo programmed cell death, this would have an impact on cancer."

Those interested in taking part in the next trial, click here. It is open to anybody under the age of 60 years with Lynch syndrome.

Written by Christian Nordqvist
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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