Published April 28, 2010
A five-minute colon cancer test could reduce the number of deaths from the disease by about 40 percent, a new study says.
British researchers followed more than 170,000 people for about 11 years. Of those, more than 40,000 had a "flexi-scope" test, an exam that removes polyps, small growths that could become cancerous.
The test involves having a pen-sized tube inserted into the colon so doctors can identify and remove small polyps. Researchers used the test on people in their 50s. In the U.K., government-funded colon cancer screening doesn't start until age 60.
Researchers compared those results to more than 113,000 people who were not screened. They found the flexi-scope test reduced peoples' chances of getting colon cancer by one third. It also cut their chances of dying by 43 percent. Researchers said the test needed to be done just once in a person's lifetime.
The results were published online Wednesday in the medical journal, Lancet. It was paid for by Britain's Medical Research Council, National Health Service Research & Development, Cancer Research UK and KeyMed.
Experts said the findings could make some authorities reconsider how they look for colon cancer. Worldwide, the disease causes 1 million cases and 600,000 deaths every year.
In Britain, people aged 60 to 74 are tested every other year with a fecal blood test. In the U.S., colonoscopies — 20-minute scans of the entire colon that require sedation — are common, even though no trials have proved they work for cancer screening. Use of the flexi-scope test has plummeted in the U.S. because colonoscopies are perceived as being better.
To find polyps or to detect cancer early, the American Cancer Society recommends several options for people over 50: a flexi-scope test, double-contrast barium enema or virtual colonoscopy every five years or a colonoscopy every 10 years.
"It's not for me to tell governments what to do," said Dr. Wendy Atkin, a professor of surgery and cancer at Imperial College London, who led the research. "But this is a very big effect, with a very quick and a very cheap test."
Atkin said the test only needed to be done once because polyps that grow in the bowel appear before age 60 — so any potentially cancerous growths should be caught if the test is done on people in their fifties. But the test only works on the lower bowel, so other exams, like the fecal blood test, would still be necessary.
Dr. David Ransohoff of the departments of medicine and epidemiology, University of North Carolina at Chapel Hill, North Carolina, said the Lancet findings might make doctors rethink whether the less-invasive flexi-scope test to scan the lower bowel, plus a highly sensitive fecal blood test to scan the upper bowel, could be better than a colonoscopy. Ransohoff was not linked to the study and wrote an accompanying commentary in the Lancet.
Ransohoff said the finding the test only needed to be done once in a person's lifetime was "striking" and further follow-up was necessary to see just how long this protective effect lasts.
Dr. Durado Brooks, director of prostate and colorectal cancer at the American Cancer Society, said the study results would not change their colon cancer screening guidelines.
"We have long included (flexi-scope) tests as one of our preferred tests to prevent disease," he said. "I would hope clinicians look at this information and recognize there is some value in this test."