Trial Information

Prospective Study for Evaluating Colon Polyp Histology With in Vivo Probe Based Confocal Laser Endomicroscopy

This study will be conducted at the Kansas City VA Medical Center, Kansas City, MO. The
investigators have the pCLE system that the investigators are currently using in a
multicenter study evaluating patients with Barrett's esophagus. Patients referred for
screening and/or surveillance colonoscopy will be prospectively enrolled in this study.
Inclusion criteria - referral for screening and/or surveillance colonoscopy and the ability
to provide informed consent. Exclusion criteria: prior surgical resection of any portion of
colon, prior history of colon cancer, history of inflammatory bowel disease, use of
anti-platelet agents or anticoagulants that precludes removal of polyps during the
procedure, poor general condition or any other reason to avoid prolonged procedure time,
history of polyposis syndrome or HNPCC, inability to give informed consent, inadequate bowel
preparation, allergy to fluorescein, pregnancy, and renal insufficiency. Moderate sedation
for the procedure will be administered in a standard fashion with intravenous midazolam,
meperidine or fentanyl. This will be a single arm study with all procedures being performed
with a standard white light colonoscope (CF - H180AL, Olympus America). After cecal
intubation, the colonic mucosa will be carefully visualized during withdrawal under
high-definition white light and if a polyp is detected, its characteristics will be
documented: size, location, and morphology [Polypoid (sessile, pedunculated) or
Non-polypoid: (superficial elevated, completely flat, depressed)]. Then 5ml of 10%
fluorescein sodium will be injected intravenously. Following this the pCLE probe will be
passed through the biopsy channel of the colonoscope and placed on the polyp to obtain
confocal images and video sequences. During the initial phase unblinded comparisons of the
confocal images and videos with the polyp histology (20 adenomas, 20 hyperplastic) will be
performed in order to evaluate the criteria described by the Mayo Jacksonville group (22)
that differentiate between neoplastic and non neoplastic polyps. Following this initial
phase, these criteria will be applied in a prospective manner to predict polyp histology
(100 polyps) real time during the procedure prior to their removal. Multiple confocal images
and videos of each polyp will be saved with appropriate labeling. Pathologists will be
blinded to the endoscopic and pCLE findings of the polyps. Polyp size will be assessed by
comparing with sheath of a polypectomy snare or open span of a biopsy forceps. Photo
documentation of the polyps will be performed. Polyps will then be removed in the standard
fashion with a biopsy forceps or snare and sent for histopathological evaluation. Each polyp
will be sent in a separate jar and labeled accordingly. The bowel preparation will be
evaluated and graded according to previously reported criteria (24): excellent, good, fair,
and inadequate. Patients with inadequate bowel preparation will be excluded. Complications
including gastrointestinal bleeding (requiring intervention) and perforation will be
recorded.

Outcomes:

The predicted histology of polyps based on the confocal images and videos and the
correlation with actual histology for accuracy of prediction will be the primary outcome.
Secondary outcome will be the inter-observer variability in polyp histology prediction based
on the confocal images and videos of polyps (by kappa statistics).