A short, one-off sigmoidoscopy test to locate tumors and polyps in the colon using a small camera and a flexible tube could reduce deaths from bowel cancer by 40 per cent, concluded a UK trial involving 55 to 64 year olds.
You can read a report on the trial, led by Professor Wendy Atkin from Imperial College London, and part funded by Cancer Research UK, in the 28 April early online issue of The Lancet.
Harpal Kumar, Chief Executive Officer of Cancer Research UK, said in a press statement:
“This is one of the most important developments in cancer research for years.”
Every year, more than 100 people receive a diagnosis of bowel cancer in the UK, where it is the third most common cancer. While death rates have been falling in recent decades, the disease still kills 16,000 people every year.
Most bowel cancers develop from symptomless growths called polyps, and if these are detected and removed early, it vastly increases chances of survival. Figures from Cancer Research UK suggest 9 in 10 people survive for more than five years if their bowel cancer is diagnosed at an early stage.
For the trial, Atkin and colleagues used a device called the “Flexi-Scope”, a common name for a flexible sigmoidoscopy comprising a flexible tube or endoscope that has a small camera and light at the end.
Doctors use the Flexi-Scope to examine the general health of the bowel and search for polyps in the sigmoid colon, the part of the large intestine that is closest to the rectum, which is where the tube goes in. The procedure is painless and quick, as is removing any polyps, which can be done at the same time and adds only minutes to the time it takes to do the screening.
Atkin and colleagues have been carrying out a trial using the Flexi-Scope for the last 16 years.
For the trial they recruited over 170,000 people, a third of whom were invited to have a one-off test with the Flexi-Scope. The participants were treated at 14 UK centres, and just over 70 per cent agreed to have the test, with eventually 40,674 undergoing screening with Flexi-Scope.
The researchers found that for people aged between 55 and 64, having a one-off test with the Flexi-Scope reduced their chances of developing bowel cancer by one third compared to a control group that did not have the test. The rate of death among those screened was also 43 per cent lower than that of the control group.
At a public health level, this translates to 5.2 cases of bowel cancer prevented for every 1,000 people, and 2 deaths avoided. Or in other words, screening 191 people is likely to prevent one case of bowel cancer and screening 489 people is likely to prevent one death.
For the UK this means bringing in one-off tests for bowel cancer for this age group could prevent at least 5,000 people from receiving a diagnosis of bowel cancer and save at least 3,000 people from dying of it (this is more than twice the 1,400 lives that the NHS Breast Screening Programme says it saves in England every year).
Cancer Research UK suggests that the Flexi-Scope test be added to the UK’s current bowel screening programme, which is currently based on the FOBT, or faecal occult blood test, which looks for “hidden” blood in stool samples, a possible sign of cancer anywhere in the gastrointestinal tract.
Trials show that FOBTcan reduce bowel cancer deaths by around 25 per cent, and for many countries, as in the UK, it is the main part of their bowel cancer screening programme.
The charity suggests the two tests, Flexi-Scope and FOBT complement each other: Flexi-Scope can prevent bowel cancer as well as detecting it after it has appeared, but only in part of the colon, so the FOBT still has a role in detecting early cancers further up the digestive tract.
In the UK, people aged 60 to 69 can ask for a FOBT kit they use at home to prepare and send a stool sample to a lab for testing. But the Flexi-Scope is only available for people with symptoms or with a referral from a GP or specialist.
Cancer Research UK urged whoever forms the next government of the UK to incorporate the Flexi-Scope test in the national bowel cancer screening programme. They said the test is very cost-effective, especially as it only needs to take place once every 11 years and the cost would most likely be outweighted by having to treat fewer people, and more of those who are treated would be at an earlier stage, where treatment costs are lower.
A study commissioned by the UK Department of Health reported in 2006 that a Flexi-Scope screening programme would save £28 for every person who was screened.
The risks of the test appear to be small, with no possibility of reporting false positives because doctors can only detect and remove polyps that are actually there. However, removing a polyp can cause a small amount of bleeding and there is a 1 in 50,000 chance that the tube itself can puncture or tear the bowel.
An important question is how willing people would be to have the test. Atkin and colleagues addressed this in an earlier study involving 4,400 people who underwent screening with the Flexi-Scope. They found the vast majority said they were glad they had the test and were satisfied with the procedure. 91 per cent reported mild or no pain and 97 per cent said they felt little or no embarrassment.
Another area of cost is training people to use the Flexi-Scope, and the researchers said this, and all the other factors need to be properly researched before weighing up the overall costs and benefits of introducing Flexi-Scope as part of the national screening programme.
“Once-only flexible sigmoidoscopy screening in prevention of colorectal cancer: a multicentre randomised controlled trial.”
Wendy S Atkin, Rob Edwards, Ines Kralj-Hans, Kate Wooldrage, Andrew R Hart, John MA Northover, D Max Parkin, Jane Wardle, Stephen W Duffy, Jack Cuzick.
DOI:10.1016/S0140-6736(10)60551-X
Source: Cancer Research UK.
Written by: Catharine Paddock, PhD