Attaching a transparent cap to the tip of the colonoscopy can help depress haustral folds, thereby decreasing the blind mucosal surface area and potentially improving adenoma detection rates.
Dr. Siew C. Ng and colleagues from The Chinese University of Hong Kong, Hong Kong compared the efficacy of CAC versus standard colonoscopy in polyp detection and cecal intubation rate through their analysis of 16 randomized controlled trials, including 8991 patients, published from 1997 to 2011. Their results appear in the June 5th online issue of The American Journal of Gastroenterology.
In the 12 trials that investigated polyp detection rates, there was a barely significant 8% increased proportion of patients with polyps detected with CAC compared with standard colonoscopy. An estimated 27 patients would have to undergo CAC for polyps to be detected in 1 extra patient.
Six trials that specifically compared the proportion of patients with adenomas detected failed to find a significant difference between CAC and standard colonoscopy.
Although there was no significant difference in cecal intubation rates between CAC and standard colonoscopy, CAC was associated with a significant reduction in mean cecal intubation time by about 38 seconds, compared with standard colonoscopy. There was, however, no significant difference between the 2 approaches in total colonoscopy time.
“The difference in polyp detection is probably due to increase in detection of non-adenomatous polyps,” the researchers conclude. “Larger, well-designed studies focusing on adenomatous polyps are needed.”
“The choice to use a cap would remain at the discretion of the endoscopist,” they add. “It may be beneficial during screening colonoscopies, when training junior endoscopists, or as a rescue approach during failed colonoscopy.”