Trial Information

Diagnosis of Intraepithelial Neoplasia in Patients With Long Standing Ulcerative Colitis With Chromoscopic Guided Endomicroscopy

Ulcerative colitis (UC) is an immune cell-mediated inflammatory bowel disease characterized
by mucosal ulcerations, rectal bleeding, diarrhea, and abdominal pain. Patients with long
standing UC face an increased risk for development of colitis associated colorectal cancer.
Factors associated with increased risk for cancer development include the duration of the
disease, extensive colonic involvement (pancolitis, backwash ileitis), primary sclerosing
cholangitis and severe chronic active inflammation. Based on these observations,
colonoscopic surveillance in patients with long-standing UC is highly recommended.

The main objective of surveillance colonoscopy in UC is to detect neoplasia at a surgically
curative and preferably pre-invasive stage. However, in contrast to sporadic colorectal
cancer, the growing pattern of neoplastic tissue in UC is often flat and multifocal.
Therefore, significant lesions during conventional colonoscopy in UC are frequently
overlooked. Chromoscopy with topically applied dyes such as methylene blue or indigo carmine
facilitates the endoscopic detection of flat, circumscribed colitis associated neoplastic
changes in UC. In fact, five controlled studies showed that the diagnostic yield for the
detection of intraepithelial neoplasia (IN) using chromoscopy is higher as compared to
conventional colonoscopy with random biopsies. Based on the above studies, chromoscopy has
recently been considered for incorporation into US guidelines for surveillance of patients
with long-standing UC. However, although this technique does allow identification of mucosal
lesions, it is not suitable for accurate endoscopic diagnosis of intraepithelial neoplasias
in UC due to the lack of cellular resolution and subsurface imaging. For endoscopy, novel
techniques allowing accurate diagnoses during ongoing examination are highly desirable and
may allow appropriate and immediate therapeutic manoeuvres (e.g. resection versus biopsy).
Recently, a miniaturized confocal microscope has been developed integrated in the distal tip
of a conventional colonoscope . This new diagnostic technology for gastrointestinal
endoscopy, denoted confocal endomicroscopy, enables histological evaluation of the mucosal
layer during ongoing colonoscopy. Furthermore, in patients screened for sporadic colorectal
cancer, surface and subsurface analysis at cellular and subcellular resolution can be used
to predict intraepithelial neoplasias (INs) with high accuracy. However, due to the time
required for examination of large surface areas, this technique is not suitable for
screening of the entire colonic surface in UC to detect neoplasias in flat mucosa.

In the present study, we employ chromoscopy to identify potential neoplastic lesions and
combine this for the first time with endomicroscopy for the endoscopic diagnosis of colitis
associated intraepithelial neoplasias in UC. Using such chromoscopy guided endomicroscopy we
will ecaluate whether the diagnostic yield diagnosing IN can be significantly increased.