Occlusive colon carcinoma: Virtual colonoscopy in the preoperative evaluation of the proximal colon

PURPOSE: To evaluate the use of preoperative virtual colonoscopy to examine the :proximal colon in patients with distal occlusive carcinomas, defined as cancers that cannot be traversed endoscopically. MATERIALS AND METHODS: Twenty-nine patients with occlusive colorectal carcinomas underwent preoperative virtual colonoscopy with use of a standard protocol. Patients with acute bower obstruction were excluded. Results of virtual :colonoscopy were compared with the findings of preoperative colonoscopy, preoperative barium enema examination, intraoperative colon palpation, histopathologic outcome, and postoperative colonoscopy and barium enema examination, where possible. RESULTS: Virtual colonoscopy helped identify all 29 occlusive carcinomas and demonstrated two cancers and 24 polyps in the proximal colon. Both synchronous cancers were confirmed intraoperatively and resected. Postoperative conventional colonoscopy in 12 patients confirmed 16 polyps identified at virtual colonoscopy and demonstrated two subcentimeter polyps missed at virtual colonoscopy. Postoperative barium enema examination was performed in two patients and helped confirm two polyps identified at virtual colonoscopy. Virtual colonoscopy successfully demonstrated the proximal colon in 26 of 29 patients examined compared with preoperative barium enema examination, which failed to adequately demonstrate the proximal colon in any patient examined. CONCLUSION: Virtual colonoscopy is a feasible and useful method for evaluating the entire colon before surgery in patients with occlusive carcinomas.