Endoscopic Tri-Modal Imaging and Confocal Endomicroscopy for the detection of neoplasia in longstanding ulcerative colitis: a feasibility study.

Patients with longstanding ulcerative colitis (UC) are at increased risk of
developing colorectal cancer and therefore undergo regular colonoscopic
surveillance. Random biopsies are taken during surveillance, since neoplasia
mainly exists in flat mucosa and is grossly invisible at conventional
colonoscopy. Random biopsies increase workload and costs for both endoscopists
and pathologists. Novel endoscopic imaging techniques like high resolution
endoscopy (HRE), autofluorescence imaging (AFI), narrow band imaging (NBI) and
confocal endomicroscopy facilitate the detection of neoplasia and improve the
discrimination of neoplastic from non-neoplastic mucosa. Hence, the use of
these new techniques might eliminate the need for taking random biopsies and
might reduce false positive biopsies as well.

The aims of this study are: 1) to evaluate the neoplasia miss-rate of AFI in
patients with longstanding UC during colonoscopic surveillance; 2) to evaluate
the feasibility of miniprobe-based confocal endomicroscopy in these patients;
3) to compare the accuracies of the combined use of AFI plus NBI with confocal
endomicroscopy for the endoscopic prediction of histopathology of detected
lesions; 4) to compare the yield of random biopsies with the yield of confocal
endomicroscopic optical biopsies.

Patients with longstanding UC will undergo colonoscopic surveillance by AFI.
All detected lesions will be inspected by NBI and confocal endomicroscopy for
prediction of histopathology. Biopsies from detected lesions will be used as
the gold standard diagnosis. After examination by AFI, random biopsies (with
HRE) will be taken according to current clinical guidelines. Before taking
these random biopsies, confocal endomicroscopy will be performed from the
corresponding sampling sites.

The endoscopic procedure is comparable to the standard procedure for regular
patient care with the exception of performing additional confocal
endomicroscopy. The use of AFI and confocal endomicroscopy do not increase the
risk of complications. The accepted risk of a diagnostic colonoscopy is minimal
(~0%).