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New study marks major advance in bowel cancer screening

Posted Apr 28 2010 12:00am
An image of a Flexi-Scope

A new one-off bowel test could reduce deaths by 40 per cent (click to enlarge)

What if having your bowel investigated with a tiny camera – just once – could greatly reduce the risk of dying from bowel cancer and of developing the disease in the first place? Striking new results from an important study show that this is very real possibility.

We don’t often use the word breakthrough – but this is one of those rare occasions. Thousands of people could be saved from developing bowel cancer because of this test and thousands more could be diagnosed early when treatment is most effective.

As Harpal Kumar, our Chief Executive Officer, said, “This is one of the most important developments in cancer research for years.”

For the past 16 years, Professor Wendy Atkin from Imperial College London has been coordinating a trial of a test called flexible sigmoidoscopy or, more commonly, ‘Flexi-Scope’. It involves a tube called an endoscope , which has a tiny camera and light at the end of it.

Cancer Research UK is proud to have supported much of Professor Atkin’s work, including part-funding this trial.

But there’s a lot of potential for preventing the disease too. Most bowel cancers develop from symptomless growths called ‘ polyps ’ or ‘adenomas’. If doctors can find these, they can remove them before they have a chance to develop into cancer. This is a painless procedure and is usually quick, adding on a matter of minutes to the time needed to do the test itself.

For these reasons, Flexi-Scope could be a great way of screening people for bowel problems, and detecting or preventing cancer. But, as with any screening programme, we needed some hard evidence that it would actually save lives. Professor Atkin’s new results, published in the Lancet , show just that, and they are very promising.

What did the trial show?

Professor Atkin’s team recruited over 170,000 people to the trial, a third of whom were invited for one-off screening using Flexi-Scope. Just over 70 per cent of those invited chose to attend and, all in all, the teams screened 40,674 people.

She found that for people aged between 55 and 64, a one-off Flexi-Scope examination reduced people’s chances of developing bowel cancer by a third, compared to a control group who weren’t screened. It also reduced the death rate from bowel cancer by 43 per cent.

All in all, Prof Atkin showed that for every 1,000 people who are screened, 5.2 cases of bowel cancer can be prevented and two deaths could be avoided. Put another way, you would need to screen 191 people to prevent one case of bowel cancer and 489 people to prevent one death. And these figures can only get better with time.

But the figures are only half the story. We also need to consider the size of the prize. Bowel cancer is the third most common cancer in the UK and more than 100 people are diagnosed every day. Death rates have been falling in the past four decades, but the disease still kills around 16,000 people every year.

The prospect of preventing such a common disease that costs so many lives is extremely exciting. Doing so with a one-off five-minute test, whose benefits last for at least 11 years, is even better.

Based on the data, Prof Atkin conservatively estimates that the one-off screen could prevent at least 5,000 people from being diagnosed with bowel cancer and at least 3,000 people from dying from the disease.

To put that into perspective, official figures from the NHS Breast Screening Programme say that breast screening saves 1,400 lives a year in England. That figure is controversial but even so, adding Flexi-Scope to the existing national bowel screening programme could save twice as many lives.

A different screening programme?

The UK already has a bowel screening programme . It uses a different test called the “faecal occult blood test” or FOBT, which looks for hidden traces of blood in stools. In England and Wales, people are invited for screening between the ages of 60 and 69. They are sent a kit to use in the privacy of their own homes, and results are sent to a lab for testing.

The FOBT is also an effective way of screening for bowel cancer. Trials have found that it can reduce death rates from the disease by around 25 per cent, and countries all over the world have used it as the basis of bowel cancer screening programmes. However, Prof Atkin’s latest results suggest that the Flexi-Scope is even more effective. And, crucially, it can prevent bowel cancer as well as detecting it after it has appeared.

The two tests should complement each other well. The Flexi-Scope can only scan the lower part of the bowel. It won’t be able to detect polyps or cancers in the upper reaches, so the FOBT still has a role in detecting early cancers there.

The Flexi-Scope test is currently available in the UK, but only for people with symptoms or after a referral from a GP or specialist. Based on the new results, this could change in the future.

In fact, Cancer Research UK thinks the findings are so promising that we are calling on the UK governments to incorporate the Flexi-Scope as part of the national screening programme for bowel cancer alongside the FOBT test.

We think the Flexi-Scope test should probably be offered to people from their late 50s. This is because most polyps appear in the lower bowel before the age of 60 and slowly develop into cancer over the next few decades.

Will it be acceptable?

A key question is whether people will accept the new test. The signs suggest they will. In an earlier study of 4,400 people who went through Flexi-Scope screening, Prof Atkin showed that virtually all of them were glad they had the test and were satisfied with the procedure. Meanwhile, 91 per cent reported mild or no pain, and 97 per cent said they felt little or no embarrassment.

The risks of the test appear to be small. Removing a polyp can cause a small amount of bleeding and there is around a 1 in 50,000 chance that the tube can tear the bowel. There isn’t really a risk of a false-positive, because doctors can only detect and remove polyps if they are there.

And to top off the good news, the Flexi-Scope test could be very cost-effective, especially since it only needs to be done once in an 11 year span. The test’s costs would probably be outweighed by the fact that fewer people need to be treated, and treatments are cheaper for early-stage cancers. In 2006, a study commissioned by the UK Department of Health suggested that a Flexi-Scope screening programme would actually save £28 for every person who was screened.

Of course, Prof Atkin says that there are many practical choices that would affect these calculations, and they would need to be repeated using data from the actual trials. There’s also the pressing need to train people with the endoscopes if Flexi-Scope becomes more widely used.

The new results have closed the door on 16 years of research and opened new and exciting ones. The big question now is whether the country will step through them.

Ed

More from Cancer Research UK:


Reference:

Atkin W et al (2010). Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial The Lancet : 10.1016/S0140-6736(10)60551-X

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