Virtual colonoscopy dints referrals for optical method

June 5, 2006

Gastroenterologists and other GI specialists are cautiously embracing virtual colonoscopy while calling for more data to shore up favorable experience.

Gastroenterologists and other GI specialists are cautiously embracing virtual colonoscopy while calling for more data to shore up favorable experience.

That experience was presented in May at the Digestive Disease Week conference in Los Angeles, the largest international gathering of gastroenterologists, endoscopists, and gastrointestinal surgeons.

Dr. Darren C. Schwartz, a gastroenterologist at the University of Wisconsin in Milwaukee, analyzed the effects of VC on optical colonoscopy utilization. While no drop in the number of optical colonoscopy procedures performed, the number of OC referrals decreased significantly.

Researchers reviewed data from before and after introduction of VC screening at their institution.

The average number of optical colonoscopy screenings performed each month did not change significantly after VC was introduced and the percentage of optical colonoscopy exams involving removal of polyps also remained constant.

The percentage of optical colonoscopy screening referrals dropped from 247 per month to 203 per month after VC screening was initiated. The trend may be an early indicator of decreased demand for optical colonoscopy screening, according to researchers.

"This study shows a potential change in the tide of colonoscopy choices," Schwartz said. "As more medical institutions and healthcare service providers adopt and reimburse for virtual colonoscopies, we may see a significant decrease in the popularity of more traditional colonoscopy techniques.

Schwartz cautioned that differences in accuracy still exist. He said it's important for patients, especially those at high risk for colon cancer, and their physicians to carefully consider their options when choosing a screening technique.

In another study, researchers at the National Naval Medical Center focused on extra-colonic abnormalities such as calcified arteries and nodules found during VC screening.

Investigators conducted CT colonography screening on 979 asymptomatic, average risk patients. They characterized extra-colonic abnormalities as critical (requiring therapeutic intervention), moderate (requiring additional diagnostic intervention), or incidental (no further action).

Extra-colonic abnormalities were detected in approximately 16% of screenings, the most common being coronary artery calcifications (41 patients) and noncalcified pulmonary nodules (33 patients). Abnormalities were found throughout the body, including the heart and lungs, kidney, liver, bone, and other organs. While half were classified as incidental, another 33% were moderate and 15% were critical.

"Significant abnormalities requiring further action accounted for nearly half of the abnormalities we found, suggesting that by screening for colon cancer, we may offer early detection of other potentially morbid conditions in some patients," said senior author Dr. Brooks Cash, director of clinical research at the naval center.

Cash noted the increased indirect costs of virtual screening associated with extra-colonic findings. For that reason, outcomes studies need to be conducted before routine use of the procedure can be recommended, he said.

For more information from the Diagnostic Imaging archives:

Virtual colon scans bring big benefits but face big hurdles

Studies underscore value of CT colonography training

Virtual colonoscopy gets an A for safety

Tools for CT colonography advance toward clinical use