Each participant underwent CT colonography followed by colonoscopy on the same day. Preparation for CT colonography is usually the same as is used for colonoscopy, though Laudi said that a less potent laxative is sometimes used. But, the colon still needs to be emptied and clean for the CT test. Colonoscopy can be used to screen, diagnose and treat colorectal cancers, but it is considerably more invasive, carries a greater risk of complications and often requires sedation.
Overall, the virtual test found 85 percent of the colorectal cancers detected by colonoscopy. False-positive rates were 4 percent for advanced cancers and 15 percent for people with a positive FOBT.
"Virtual colonoscopy is a valid screening test for colorectal cancer, trading off a better acceptance and lesser invasiveness by comparison with colonoscopy, with the possibility of missing small polyps that may, however, not be so relevant in terms of risk of developing into cancer," Laudi said.
Because a positive FOBT indicates a strong likelihood of cancer and a need for treatment, Brooks said he wouldn't recommend CT colonography for people with a positive test unless there were some extraordinary individual circumstances that prevented the use of colonoscopy.
"The question remains whether clinicians are willing to accept a study with decreased sensitivity for the potential of increased adherence with recommended screening and surveillance guidelines," wrote Dr. Emily Finlayson from the University of Michigan, in an accompanying editorial in the same issue of the journal. "With the majority of individuals in the United Sta
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