Virtual colonoscopy missed 27% of colorectal lesions compared with conventional colonoscopy, according to a study presented Tuesday at a meeting of the American College of Gastroenterology in Baltimore.
While some physicians have argued that virtual colonoscopy may replace conventional colonoscopy for colorectal cancer screening, virtual colonoscopy, or VC, is not yet accurate enough for widespread use as a screening test for colon cancer, the report says.
The study looks at the findings of 16 studies that compared virtual colonoscopy, which uses computed tomography (CT) scans or magnetic resonance imaging (MRI) to look at an image of the inside of the colon, with more invasive conventional colonoscopy, which uses a fiberoptic endoscope. Eleven studies involving CT scan screening included 1,236 subjects, and five studies involved MRI screening on 316 subjects.
The newer technology did not always successfully identify polyps larger than one centimeter.
"VC is not an adequate screening tool for colorectal cancer," the report says.
But the results of another study, presented Tuesday at the fourth International Symposium on Virtual Colonoscopy in Boston, showed a higher sensitivity for virtual colonoscopy than for optical colonoscopy for adenomas 8 millimeters and larger, says lead author Perry Pickhardt, M.D.
This prospective trial, comparing virtual and optical colonoscopy, is the largest conducted to date and the first to evaluate an average-risk screening population, Pickhardt says. The study used a population of 1,233 asymptomatic adults and was conducted by several Department of Defense facilities over the last two years.
"Virtual colonoscopy will be ready for prime time within a year," Pickhardt says. "I agree in part that, to date, it is a moving target. We're not quite there yet. People just have to realize as the technology advances, this will very soon become an excellent screening test that's better tolerated by patients and won't require sedation, with an accuracy comparable to conventional colonoscopy."