Endoscopic Screening for Dysplasia in Patients With Longstanding Ulcerative Colitis: Classical Chromo-endoscopy Versus NBI , FICE and EPK-i.

The risk for colon cancer in patients with longstanding ulcerative colitis exceeding the rectum is increased and therefore patients should be enrolled in a surveillance program eight years after the diagnosis. Surveillance endoscopies are advised 8 to 10 years after the diagnosis of ulcerative colitis. The first decade every 3 years, the second decade every 2 years and thereafter every year Until today, most official international guidelines for endoscopic screening in patients with ulcerative colitis advise to take 4 random biopsies every 10 centimeters (with a minimum of 32) and of each suspected visible lesion using standard white light endoscopy.

These guidelines are merely based on consensus during expert opinion meetings rather than evidence based.

However, some studies have shown that the sensitivity for the detection of dysplasia during colonoscopy in patients with ulcerative colitis can significantly be enhanced by using chromo-endoscopy. These studies used methylene blue or indigo carmine as a contrast agent with or without high magnification endoscopy. Chromo-endoscopy guided targeted biopsies significantly reduced the number of biopsies for each procedure and detected more neoplastic lesions. It was therefore concluded that colonoscopy with chromo-endoscopy guided biopsies is more efficient and cost saving. Chromo-endoscopy with targeted biopsies is an alternative to white light endoscopy with random biopsies every 10cm. The European Crohn and Colitis association now suggests that the use of methylene blue or indigo carmine chromoendoscopy is an alternative to random biopsies for appropriately trained endoscopists and is superior to random biopsies in the detection rate of neoplastic lesions In this study we want to compare chromoendoscopy with targeted biopsies as the gold standard with new new endoscopic image techniques called virtual chromoendoscopy.

From 2005 new endoscopic imaging modalities have been commercialized and are now generally available to gastroenterologists. They all claim a theoretical advantage in comparison to standard white light high resolution video endoscopy. These new techniques are called virtual chromoendoscopy (VC). There are three different systems developed by the three major competitors of endoscopic equipment: Olympus, Pentax and Fujinon.

Narrow-Band Imaging (NBI) is developed by Olympus inc. and selectively uses certain wavelengths of the visible light leading to a shift in the excitation spectrum towards blue light. The intensity of the blue bandwidth is also enhanced. This leads to a more superficial penetration of the emitted light into the mucosa of the intestine and enhancement of more superficial structures (e.g. irregularities, small flat lesions or polyps) and small superficial mucosal vessels (indicative of neoplasia).