This is a test in which a thin, black, flexible tube with a lighting system on the end is
passed through the anus, into the rectum, in order to examine the large bowel or intestine,
also called the colon. Colonoscopy is a very good test for examining the colon for polyps
(warty growths that can turn into cancer), but it is not perfect. In fact, about 30% of
polyps that are under 5 mm (about 1/5 of an inch) in size are missed during colonoscopy
because they are hiding behind folds and bends in the colon. This research study is being
done to determine if performing colonoscopy with a cap on the tip of the colonoscope will
reduce the miss rate for polyps. A cap is a clear plastic hood that fits on the tip of the
colonoscope and sticks out about 1/3 of an inch. During colonoscopy, the cap can be pressed
against a fold or ridge in order to flatten it, so that the lining on the other side can be
more easily seen. This may reduce the miss rate for colon polyps.
Patient will undergo tandem colonoscopy on the same day using propofol sedation. Patients
will undergo one colonoscopy without the cap and a second colonoscopy with the cap on. We
will endeavor to keep the total examination time equal between the groups and approximately
six minutes. The order in which patients receive the two colonoscopies (i.e. cap or without
cap first) will be randomized. Any polyps detected during the first colonoscopy will be
removed during that procedure. During the withdrawal phase, the time for examination will
be measured with a stopwatch, and the stopwatch will be stopped at any time a polyp is
located and restarted when the polyp has been removed and retrieved. The stopwatch will
also be stopped for suctioning fluid or washing debris from the colon surface. Any polyp
detected and removed during the first colonoscopy will be counted as the detection for that
procedure. During the second colonoscopy, all polyps will also be removed when detected.
Any polyp identified and removed during the second procedure will be counted as a miss for
the first procedure. All polyps will be sent separately for pathologic evaluation. The
time required to remove and retrieve polyps with and without the cap on will be measured
using a stopwatch as a secondary end point. The primary end point will be the miss rate for
colonoscopy with the cap and colonoscopy without the cap.
- 50 years of age or older, undergoing scheduled colonoscopy and able to give informed
- Previous surgical resection of the colon or rectum
- ASA class III or higher
- Inflammatory bowel disease
- Current use of anticoagulants.