Colonoscopy for screening of colorectal cancer. What are the news? Review
The goal of every routine endoscopy in the gut is the early diagnosis of malignant and premalignant changes of the mucosa. Chromo- and magnifying endoscopes are exciting new tools and offer detailed analysis of the colonic mucosal surface and pit pattern architecture. This review summarizes recent advances in endoscopic characterization of colorectal lesions using magnification endoscopy and chromoendoscopy. Surface analysis of the colon using chromoendoscopy allows a prediction between nonneoplastic and neoplastic lesions with high specificity. The precise delineation of the borders and a more detailed macroscopic analysis of the lesions are further advantages. In particular, flat adenomas and early depressed cancers are now more frequently recognized in Western countries suggesting that significant lesions were overlooked by conventional endoscopy in the past. Furthermore, chromoendoscopy can be used in a targeted fashion to screen for sporadic adenomas. Finally, in surveillance colonoscopy, patients with longstanding ulcerative colitis have a valuable benefit if targeted biopsies are performed to detect intraepithelial neoplasias after panchromoendoscopy with methylene blue. Although there is a long learning curve, chromoendoscopy should thus belong to every endoscopists armamentarium. However, detailed knowledge about the technique, dyes and specific staining patterns are mandatory before the yield of screening or surveillance colonoscopy can be increased. The new detailed images seen with magnifying chromoendoscopy are unequivocally the beginning of a new era where new optical developments will allow a unique look on cellular structures.
R. KIESSLICH, M. JUNG, P.R. GALLE, M.F. NEURATH