Analysis Of Advanced Proximal Colonic Neoplasia Without Index Polyp In The Rectosigmoid.

Background & aim : Colorectal adenoma is known as a precursor of colon cancer. Current recommendation is to perform total colonoscopy whenever any adenoma is detected during screening sigmoidoscopy. Most previous studies which did focus their interest on proximal advanced lesions only used total colonoscopy in case with index polyp in the rectosigmoid. The aim of this study was to evaluate the frequency of the colonic neoplasia above the rectosigmoid without an index polyp in our colonoscopy population. Methods : Colonoscopic and histologic data were analyzed from all patients on whom total colonoscopy was performed between 1995 and 1999 in Anam hospital of Korea university medical center. Advanced neoplasia was defined as cancer or adenoma>10mm in diameter, adenoma with villous component, or high grade dysplasia. Patients with polyposis syndrome, inflammatory bowel disease, previous colorectal neoplasia were excluded. Results : Total colonoscopy was performed on 6672 patients. 573 patients(Male 392 Female 181, Mean age 54.3 years) had at least one colorectal neoplasm of which 48 percent had neoplasm above rectosigmoid. The analysis of patients with proximal colonic neoplasia without an rectosigmoidal adenoma were summerized in table. Conclusion : Thirty-five percent of all patients with neoplasia had no index polyp in the rectosigmoid and 12 percent of these had at least one advanced proximal neoplasm without index polyp.