Behind the headlines: Could screening cut bowel cancer by more than 40%?

A one-off bowel cancer screening test could cut deaths from colorectal cancer by 43 per cent, according to news reports.

Colon cancer: research suggests deaths could be cut by nearly half (Photograph: Zephyr/SPL)
Colon cancer: research suggests deaths could be cut by nearly half (Photograph: Zephyr/SPL)

Professor Wendy Atkin and colleagues at Imperial College London randomly assigned 170,432 people to be invited for colorectal screening using flexible sigmoidoscopy or not contacted.

After 11.2 years of follow-up, a total of 2,524 patients were diagnosed with colorectal cancer and 538 died from the disease.

The researchers found that, among those who underwent screening, incidence of all colorectal cancers was 33 per cent lower compared with the control group.

Incidence of lower colon and rectal cancer was reduced by 50 per cent.

How significant are the findings?
The researchers found that 59 per cent of the 215 colorectal cancer cases in the screened group were detected during the examination.

Very few cases per year were detected in the 11 years post examination - suggesting that screening has a lasting protective effect.

The paper's authors said that introducing this type of screening would be cost effective because lower incidence would reduce costs associated with treating colorectal cancer.

They concluded: 'The results from our trial show that flexible sigmoidoscopy is a safe and practical test and, when it is offered only once to people between ages 55 and 64 years, confers a substantial and long-lasting protection from colorectal cancer.'

Should the technique be added to existing screening?
In an accompanying editorial, Professor David Ransohoff of the University of North Carolina, said that although sigmoidoscopy screening is not perfectly protective, its benefits compare favourably with other types of cancer screening, such as mammography for breast cancer and PSA testing for prostate cancer.

Further benefits to incidence may be seen once longer-term follow-up trials in the UK and Norway are completed, he said. He concluded that the UK study must be regarded as 'the most reliable evidence about the size of the reduction in colorectal cancer for 10 years after endoscopic examination of the (lower) colon'.

Bowel Cancer UK chief executive Deborah Alsina welcomed the findings and said the charity supported proposals for a one-off flexible sigmoidoscopy test to sit alongside existing screening.

She added: 'We also call on the next government to continue to invest in bowel cancer prevention and awareness programmes because, although these results are very significant, screening cannot prevent nor detect all bowel cancers.'

The DoH welcomed the 'exciting' research and said its independent Bowel Screening Advisory Committee would meet on 13 May to discuss the feasibility, practicalities and cost-effectiveness of bringing flexible sigmoidoscopy into the NHS Bowel Cancer Screening Programme.

Informing Patients
  • Screening for colorectal cancer using flexible sigmoidoscopy can cut incidence by 33 per cent.
  • Associated mortality was also reduced by 43 per cent.
  • Researchers said the technique was quick, safe and cost effective, and the DoH is considering introducing it alongside existing screening.
Stephen Robinson

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