European trial data bolster argument for CT colonography

October 16, 2007

A new multicenter study from Italy shows virtual colonoscopy is comparable to gold standard optical colonoscopy for detecting suspicious lesions in patients at higher than normal risk for colorectal cancer.

A new multicenter study from Italy shows virtual colonoscopy is comparable to gold standard optical colonoscopy for detecting suspicious lesions in patients at higher than normal risk for colorectal cancer.

European data were presented at the Eighth Annual Symposium on Virtual Colonoscopy in Boston on Oct. 15, on the heels of positive news for virtual colonoscopy in a prominent New England Journal of Medicine study from the University of Wisconsin and as a preview of results from the American College of Radiology Imaging Network study.

"We have seen strong data from the American side of the ocean. And you will be happy to hear good news from Europe, very similar to the ACRIN trial," said Dr. Andrea Laghi, an associate professor of radiology at University of Rome La Sapienza.

The days when people questioned the performance of CTC appear to be over, based on all of the new data, said Laghi, who presented results from the IMPACT study, a multicenter Italian trial of 934 patients at higher risk for colorectal cancer. Principal investigator Dr. Daniele Regge of Italy's Institute for Cancer Research and Treatment is also a presenter at the symposium this week.

People considered at risk, based on the multicenter trial protocols, included those who had previously undergone polypectomies and those who had a first-degree relative with an adenoma or adenocarcinoma detected between the ages of 40 and 65.

The study's radiologists had experience reading at least 50 CTC studies, and the scanners used had at least four detector rows. Two-D as well as 3D interpretation techniques were used. Selection of a bowel preparation was left to the discretion of the provider, as was the means of colonic distention (air or carbon dioxide). Fecal tagging was not part of the study protocol. After undergoing CTC, patients proceeded to conventional colonoscopy, used as the reference standard.

Among 934 patients participating in the trial, researchers picked up 203 adenomas, 174 cases of advanced neoplasia, and 42 colorectal cancers.

For adenomas greater than or equal to 10 mm, per-patient results showed a sensitivity of 90.7% (117/129), specificity of 84.6% (681/805), and accuracy of 85.4% (798/934).

For adenomas greater than or equal to 6 mm, per-patient results were 84.2% sensitivity (171 of 203), 90.4% specificity (661 of 731), and accuracy of 89.1% (832 of 934).

The results suggest CTC could be introduced as an alternative for surveillance of patients with an increased personal risk or a family history of colorectal cancer, the researchers said.

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