Despite Advances in the Accuracy of CT Colonography in Detecting Polyps, Digestive Health Experts Urge Patients to Consider Risks and...(none occurred in the CTC group. Accor...),Health

According to Dr. Johnson, "The nonrandomized design of this study is problematic. The higher rate of cancer in the OC group suggests that the study populations were different, and a higher percentage of patients in the OC group might have received previous negative screening test results -- such testing would select for a lower rate of cancers and advanced adenomas in the colonoscopy group and potentially bias to higher detection in the CTC cohort. Also, the rate of perforation in the colonoscopy arm was twice what is expected in a screening population. Thus, we need additional information to interpret this nonrandomized comparison before we can generalize the results to clinical practice."

Evaluating the Potential of CT Colonography - What Patients Should Know

When evaluating new potential screening technologies, including CT colonography, the ACG has focused its evaluation on several pieces of evidence including: sensitivity for identification of polyps of various sizes, standards for polyp removal, correlating patient risks (in this case from radiation exposure), frequency of exams and the economic impact to the healthcare system of separate diagnostic and therapeutic exams.

An important reality of CT colonography is the likelihood that patients will need a follow-up with optical colonoscopy. Of the patients undergoing CT colonography in the University of Wisconsin study published in NEJM, 7.9 percent were referred for optical colonoscopy for removal of potentially pre-cancerous polyps at least 6mm in size. Earlier findings by Dr. Pickhardt and his colleagues in 2004, at least 30 percent of patients undergoing virtual colonoscopy required conventional colonoscopy to remove polyps 6mm or larger.

ACG notes that the CTC technology requires the same bowel preparation as optical colonoscopy. There is also evidence that due to the insertion of a tube in the rectum and insufflation of the abdomen with
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