There are two categories of explanations for poor right colon protection from colonoscopy. One is that differing biologic factors between right and left colon cancers prevent us from achieving effective cancer prevention. The second category of explanations involves technical issues in colonoscopy performance that may affect right colon detection, including failed cecal intubation, poor preparation (which affects the right colon preferentially), and flat lesions and serrated polyps, both of which are more common in the right colon and easier to miss at colonoscopy, compared with traditional adenomas.
We can probably correct a significant portion of this problem by improving colonoscopy performance. First, everyone should use split-dose bowel preparations. There are now 10 randomized, controlled trials showing that splitting the prep—giving half of it on the day of the procedure—improves the preparation in the ascending colon. Second, we need all colonoscopists to photodocument the cecum. Finally, increased awareness and perhaps special training are needed to improve detection of flat and serrated polyps.
We have a lot of information that adenoma detection is operator-dependent and varies dramatically between endoscopists. Colonoscopists should now be measuring their adenoma detection rates. We also need to figure out what serrated lesion detection rates should be over the next few years and institute quality indicators for this end point. We must reduce the operator dependency of colonoscopy. It's a flaw in the strategy when a procedure that is so important for prevention of a common cancer is operator dependent.
DOUGLAS K. REX, M.D., is distinguished professor of medicine at Indiana University, Indianapolis, and director of endoscopy at Indiana University Hospital, Indianapolis.
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