Experts call for new national screening programme for colorectal cancer

BMJ 2010; 340 doi: (Published 27 April 2010) Cite this as: BMJ 2010;340:c2344
  1. Jacqui Wise
  1. 1 London

    Experts on cancer have called for a new national screening programme for colorectal cancer, with all 55 year olds in the United Kingdom to undergo a one-off 5 minute sigmoidoscopy examination.

    The call comes after the publication this week of a 16 year study showing that a single flexible sigmoidoscopy examination in men and women aged between 55 and 64 reduced the incidence of bowel cancer by a third (hazard ratio 0.67 (95% confidence interval 0.6 to 0.76)) and bowel cancer mortality by 43% (0.57 (0.45 to 0.72)), in comparison with a control group.

    Harpal Kumar, chief executive of Cancer Research UK, called on the next government to add the test to the existing national bowel screening programme as one of its first priorities. “I think it is a no brainer,” he said. “This is the most important development in cancer research for years. We very rarely see results as good as this.”

    Bowel cancer is the third most commonly diagnosed cancer in the UK and the second most common cancer killer, after lung cancer. One in 20 people in the UK will develop bowel cancer in their lifetime, half of whom will die from it.

    The randomised trial followed more than 170 000 people over an average period of 11 years, of whom 40 674 underwent a sigmoidoscopy examination. The study, published online in the Lancet, took place at 14 UK centres (doi:10.1016/S0140-6736(10)60551-X).

    Flexible sigmoidoscopy examines only the lower part of the bowel, where two thirds of colorectal cancers and adenomas occur. The examination can be carried out by doctors or by specially trained nurses in outpatient clinics. Any small polyps found are removed straight away, as they can become cancerous if left untreated. In the study patients were referred for colonoscopy if any of the polyps were considered to be high risk—if they were over 1 cm in size, for example. Colonoscopy is an examination of the whole bowel and is a longer procedure that would not be suitable for population screening.

    During the follow-up period 2524 participants were given a diagnosis of colorectal cancer, 1818 in the control group and 706 in the screening group.

    The study’s leader, Wendy Atkin, professor of biosurgery and surgical technology at Imperial College London, said, “There has never before been trial evidence that shows that removing polyps reduces cancer incidence. This one-off 5 minute examination produces a big effect, reducing mortality by 43%.”

    Professor Atkin said that to prevent one cancer 191 patients must be screened and that for every 400 people screened one life would be saved. But she said she expected the benefits to prove even greater with even longer follow-up.

    The current bowel cancer screening programme, which uses faecal occult blood testing, is offered to patients in their 60s. This method of screening is offered every two years in England, Scotland, and Wales, but the exact age groups that qualify for screening vary from country to country. 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.

    Professor Atkin said that the new test should dovetail with this existing programme. She said that the age of 55 would be the ideal time to screen, as most polyps are already evident by this age and can be easily and safely removed before they become cancerous. The current screening programme using faecal occult blood testing should continue, however, as this identifies cancers in the whole of the colon, not just in the lower part.

    The cost of introducing a new national screening programme has not been calculated, but earlier studies have shown that it would be cost effective, because of the savings made on treatment of colorectal cancer.

    Mr Kumar said, “Incorporating flexible sigmoidoscopy into the existing screening programme could potentially save as many lives every year as the current breast cancer screening programme and maybe even more.”

    Writing in an accompanying comment in the Lancet, David Ransohoff, from the department of medicine and epidemiology at the University of North Carolina, said that although sigmoidoscopy screening is not perfectly protective, “the good news is that this size of benefit is large for any cancer screening test, certainly compared with mammography for breast cancer or assay of prostate specific antigen for prostate cancer.”

    The trial was funded by the UK Medical Research Council, Cancer Research UK, the UK National Institute for Health Research, and the medical equipment manufacturer KeyMed.


    Cite this as: BMJ 2010;340:c2344


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