This article waslast modified on 10 July 2017.
The earlier bowel cancer is diagnosed the better, with survival rates as high as 90% when tumours are localised. Two-thirds of cancers and pre-cancerous protrusions on the bowel wall called polyps are found in the lower parts of the large bowel - the rectum and the sigmoid colon. Examination of these parts of the bowel is carried out with a flexible lighted instrument called a sigmoidoscope or ‘Flexi-Scope’. Screening with this instrument has the potential to prevent bowel cancer because pre-cancerous polyps detected during sigmoidoscopy can be removed. Flexible sigmoidoscopy takes about five minutes, is safe and is well accepted by those examined. Professor Wendy Atkin from the Department of Surgery and Cancer at Imperial College London led a large multi-centre controlled trial to find out whether a single Flexi-Scope examination of people between 55 and 64 years old could reduce bowel cancer incidence and deaths. The trial was based on findings that most people who develop cancer in the lower part of the bowel have developed a pre-cancerous polyp by the age of 60.

Screening was carried out on 57,099 participants while 112,939 unscreened people formed a control group. The results, after follow-up for an average of eleven years, were published online in the Lancet on 28 April 2010. The incidence of cancer in all parts of the large bowel was 33% lower in those screened than in the controls, and deaths were 43% lower. Cancers in the lower part of the large bowel (the part examined at screening) were reduced by half. Very few new cancers developed in this part of the bowel after screening with polyp removal in the 11 or so years of follow-up.

Professor Atkin said "Our study shows for the first time that we could dramatically reduce the incidence of bowel cancer, and the number of people dying from the disease, by using this one-off test. No other bowel cancer screening technique has ever been shown to prevent the disease. Our results suggest that screening with Flexi-Scope could save thousands of lives." The chief executive of Cancer Research UK said “This is one of those rare occasions to use the word breakthrough. It is extremely rare to see clinical trial results as compelling as these.”

The current screening method for bowel cancer, called the faecal occult blood test, looks for traces of blood in stools and helps to detect cancer at an early stage. In the UK routine screening using this test is offered every two years for older people in England, Scotland and Wales and the roll-out of screening in Northern Ireland started this year. This method of screening has been shown to reduce mortality from colorectal cancer by 25% in people who use the test, but it has not been shown to reduce the risk of developing cancer. The test can be positive in tumours of the first part of the large bowel, a part not examined by the Flexi-Scope.

Cancer Research UK is calling on the new Government to add the Flexi-Scope test to the existing national bowel screening programme as one of its first priorities. Its chief executive said that such a programme would save thousands of lives and spare tens of thousands of families the anxiety and suffering associated with a cancer diagnosis, whilst also saving the NHS money.