Colonoscopies Should Last at Least 6 Minutes
Study shows higher detection rate with longer exams
WEDNESDAY, Dec. 13, 2006 (HealthDay News) -- Doctors who perform colonoscopies for early detection of colorectal cancer get better results if they spend at least six minutes looking for abnormal growths, a new study shows.
The study recorded the experience of 12 experienced gastroenterologists who did 7,882 colonoscopies, 2,053 of them for patients who'd never had a colonoscopy. In 501 of those first-time -- or screening -- exams, the amount of time spent was less than six minutes.
Those exams were the least productive. In all, cancerous or precancerous growths were detected in 23.5 percent of those patients examined. But such growths were detected in only 11.8 percent of exams where the period of examination -- called withdrawal time -- was six minutes or less; growths were detected in 28.3 percent of exams with a withdrawal time of more than six minutes.
"We think our data suggest that if the goal of colonoscopy is to detect and remove polyps, spending slightly more time in the procedure seems to translate into a better outcome for patients," said study co-author Dr. Robert L. Barclay, a partner in Illinois-based Rockford Gastroenterology Associates.
The findings are published in the Dec. 14 issue of the New England Journal of Medicine.
"This basically reinforces and provides evidence for the quality recommendations that have already been made," said Dr. Durado Brooks, director of colorectal cancer for the American Cancer Society.
Withdrawal time is "a very important measure of the quality of colonoscopy," Brooks said, and the U.S. Multisociety Task Force on Colorectal Cancer has recommended a minimum withdrawal time of six minutes.
"This study clearly shows that six minutes is a critical point, and those patients who had less had a strikingly low rate of adenoma [growth] detection, and there is at least a suspicion that the cancer detection rates would be lower," he said.
Brooks applauded the report. "I'm not sure that there has been a study as well done as this one showing a marked difference between withdrawal rates less than six minutes and more than six minutes," he said.
Barclay said the members of his medical group decided to do the study because "we do a lot of screening in our practice, with an increasing volume causing us to spend a disproportionate amount of time on it, and we wanted to make sure we were doing a decent job."
The results of the study have led to a change in the way colonoscopy is done by the group, he said.
"We've reviewed these results, and they were so impressive that we now take an extended minimum amount of time," Barclay said. "We have measured detection rates for a withdrawal time of eight minutes, and we found that with that simple step, there was a dramatic increase in polyp detection among all our physicians."
Learn more about colorectal cancer from the U.S. Centers for Disease Control and Prevention.