By Clare Murphy
Health reporter, BBC News
Not all polyps will turn into cancer
A brief one-off screening test could prevent thousands of people dying from bowel cancer every year, a study published in the Lancet suggests.
There are now calls for the test to be rolled out across the UK after results from 200,000 people aged 55-64 found it cut deaths by 43% over 10 years.
Cancer Research UK described the results from the Imperial College, London, study as a "rare breakthrough".
Independent advisers will consider the test, the Department of Health says.
The independent bowel cancer screening committee will discuss whether it would be cost-effective to incorporate the procedure - known as sigmoidoscopy - into the UK's screening programmes.
Scientists from Imperial College, London, who carried out the research, argue the costs would be outweighed by the savings generated through reducing the incidence of the disease, the UK's second biggest cancer killer.
The current screening method for bowel cancer looks for traces of blood in the stools, one of the key symptoms of colorectal cancer. If this is found, the patient is referred for further investigation.
This test - using a flexible scope little wider than a pen to find and remove polyps, the precursors to cancer - is believed to reduce the death rates from the disease by 25% for those who use it.
But by finding and removing polyps - the mainly symptomless growths which can become cancerous - a sigmoidoscopy could stop the disease developing in the first place in the lower bowel.
Two thirds of colorectal cancers occur here.
Easier to conduct than a colonoscopy, which is not suitable for the general population because it requires sedation and can be a lengthy process because the entire bowel must be examined, a sigmoidoscopy can be carried out by a nurse and does not require any pain relief. Laxatives are taken in advance to clear the bowel.
A one-off examination of over 40,000 men and women aged between 55 and 64 in which any polyps were detected and removed reduced the number of cases of the disease by one third, and deaths by 43%, when compared with a group who received no intervention.
It seems likely to reduce colon cancer mortality considerably if it is made widely available
Professor Jon Rhodes
British Society of Gastroenterology
They were followed for an average of 11 years, and lead researcher Professor Wendy Atkin said the results showed people would only need one test in a lifetime.
Combined with the existing blood test to detect any cancers developing further up the colon, "thousands of lives could be saved", she said.
Some 16,000 people die from bowel cancer every year. If the results of this study were extrapolated, about 3,000 would be saved.
Researchers calculate that one life would be saved for every 400 people screened, which compares favourably with breast cancer screening - where the figures are 500 mammograms for every life saved. The main cost would be recruiting the specialist nurses needed to carry out the examination.
"We don't often use the word breakthrough, but there is a tremendous opportunity to use this procedure to push bowel cancer back down the league table of cancer cases in the UK," said Harpal Kumar, head of Cancer Research UK, which helped fund the research.
"Cancer Research UK is calling on the next government to add the test to the existing national bowel screening programme as one of its first priorities.
"Such a programme, backed by all UK governments, would save thousands of lives, whilst also saving the NHS money."
Bowel Cancer UK has also called for the test to be added to the existing screening programme.
And Professor Jon Rhodes, of the British Society of Gastroenterology, described the results as "very exciting".
The British Society of Gastroenterology would welcome the establishment of early pilot centres to establish further data on service delivery and uptake in routine NHS practice," he said.