Virtual Colonoscopy Boosts Screening Rates 55 Percent

Patients voting with their feet strongly preferred noninvasive CT colonography over traditional colonoscopies, Dutch researchers have found.

In a report published online Nov. 15 in The Lancet Oncology, Esther M. Stoop, MD, Evelien Dekker, MD, and colleagues found that 34 percent of patients invited for CT colonography screening participated, compared to 22 percent of colonoscopy invitees. In addition to putting data behind the suspicion that patients are more apt to submit to virtual colonoscopy than the physical variety, their work also offers insights into the relative accuracy of the two procedures.

The randomized controlled trial involved residents of Rotterdam and Amsterdam, Netherlands ages 50 to 75. Stoop and colleagues sent invites for colonoscopy and CT colonography at a 2:1 ratio, with 5,924 colonoscopy invitations and 2,920 CT colonography invites going out from June 2009 to August 2010. They found the response rate to be 55 percent higher for CT colonography.

They found CT colonography accuracy for advanced neoplasia to be somewhat lower: 6.1 per 100 participants for CT colonography versus 8.7 per 100 who did colonoscopy. But taking into account the higher ratio of CT colonography participation, the differences all but evaporated to 1.9 per 100 invitees for colonoscopy and 2.1 per 100 invitees for CT colonography.

“Participation in colorectal cancer screening with CT colonography was significantly better than with colonoscopy, but colonoscopy identified significantly more advanced neoplasia per 100 participants than did CT colonography,” the researchers summarized. “The diagnostic yield for advanced neoplasia per 100 invitees was similar for both strategies, indicating that both techniques can be used for population-based screening for colorectal cancer.”

Factors such as cost-effectiveness and perceived burden should be taken into account when deciding which technique is preferable, they added.

In an accompanying editorial, Perry Pickhardt, MD, of the University of Wisconsin in Madison, said the results spoke in favor of CT colonography, given that screening participation is half the battle.

"The issue with screening for colorectal cancer is not related to test efficacy per se, but rather to the willingness of patient participation,” he said.