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 carci nomas underwent preoperative virtual colonoscopy with use of a standard pro tocol. Patients with acute bower obstruction were excluded. Results of virt ual :colonoscopy were compared with the findings of preoperative colonoscop y, preoperative barium enema examination, intraoperative colon palpation, h istopathologic outcome, and postoperative colonoscopy and barium enema exam ination, where possible. RESULTS: Virtual colonoscopy helped identify all 29 occlusive carcinomas an d demonstrated two cancers and 24 polyps in the proximal colon. Both synchr onous cancers were confirmed intraoperatively and resected. Postoperative c onventional colonoscopy in 12 patients confirmed 16 polyps identified at vi rtual colonoscopy and demonstrated two subcentimeter polyps missed at virtu al 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 2 9 patients examined compared with preoperative barium enema examination, wh ich failed to adequately demonstrate the proximal colon in any patient exam ined. CONCLUSION: Virtual colonoscopy is a feasible and useful method for evaluat ing the entire colon before surgery in patients with occlusive carcinomas.