Accuracy of CT colonography is excellent in comparison with conventional colonoscopy for colorectal cancer screening

May 16 2005

The diagnostic accuracy of CT colonography is excellent in comparison with conventional colonoscopy for colorectal cancer screening, an analysis of previous studies shows.

Aashish Goela, MD, a researcher from the University of Western Ontario in Canada, analyzed the results of 35 studies that compared the diagnostic accuracy of CT colonography with conventional colonoscopy for detecting both average and high-risk patients with polyps or colorectal cancer greater than or equal to 10mm. After extracting the relevant and available data, he found that CT colonography had a sensitivity of 88.6% and a specificity of 95.0%, similar to conventional colonoscopy. Several other, more clinically relevant, markers of diagnostic accuracy also showed a trend of excellent accuracy.

“The single biggest obstacle to colorectal cancer screening remains patient compliance. An alternative tool such as CT colonography, which offers similar accuracy as conventional colonography but which is much less invasive, could potentially increase compliance. Colorectal cancer is both highly prevalent and highly lethal, thus any improvement in early detection promises to have a positive societal impact,” said Dr. Goela.

According to Dr. Goela, an analytic study of the current literature such as the one he conducted is the best possible way at present to ascertain the usefulness of CT colonography for screening colorectal cancer, because the randomized controlled trials that are currently underway will not yield results for many years.

“The results of my meta-analysis are very promising, and I believe they may even be somewhat conservative. I excluded data in which fecal-tagging, computer-aided diagnosis and IV contrast were used as a means to enhance the effectiveness of CT colonography because their roles were unknown when I began collecting data. As these specific components have now been shown to improve accuracy, it can likely be inferred from these results that the accuracy of CT colonography is even higher,” said Dr. Goela.

Dr. Goela will present the full results of the study on May 16 during the American Roentgen Ray Society Annual Meeting in New Orleans, LA.