Researchers also reported:
-- The sensitivity for the detection of adenomas or cancers greater than or
equal to 5 mm, 6 mm, 7 mm, 8 mm, 9 mm was 65 percent, 78 percent, 84
percent, 87 percent, 90 percent, respectively.
-- If all patients with a lesion measuring 5 mm or more on CT colonography
were to be referred for colonoscopy, the colonoscopy-referral rate based
on these study results would be 17 percent.
Study participants were asymptomatic, 50 years of age or older and scheduled to undergo routine colonoscopy. Patients were excluded if they had lower abdominal pain, inflammatory bowel disease or familial polyposis syndrome among other exclusionary criteria.
There are, however, concerns about CT colonography's failure to detect small lesions and inability to remove lesions in the colon. Although small polyps often are not cancerous they can be adenomatous polyps and have a risk of developing into cancer. If a polyp is detected through CT colonography, the patient must subsequently undergo a separate colonoscopy to remove the polyp. Most likely, this would happen on another day and the patient would require a second bowel prep before undergoing the colonoscopy.
The primary end point of this study was detection by CT colonography of large adenomas or cancers 10 mm or larger. The radiologists making the interpretations were instructed to record only lesions measuring 5 mm or more in diameter.
It has been suggested that patients with small polyps may be followed
by CT colonography at shorter intervals, without referral for colonoscopic
removal. This approach of leaving polyps behind has not been tested and it
|SOURCE American Society for Gastrointestinal Endoscopy|
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