Accuracy of colon tumor localization: Computed tomography scanning as a complement to colonoscopy.

Aim: To determine the utility of computed tomography (CT) scanning in localizing colon tumors.

Methods: At a single tertiary care teaching hospital, a retrospective chart review was conducted on patients who underwent surgery for colon malignancies between January 2004 and May 2006. One hundred and four charts containing all of the following data were reviewed: preoperative colonoscopy report, preoperative CT report, surgical operative report, tumor pathology report. The colon was divided into five segments from the cecum to the sigmoid and the location of the lesions was categorized into one of these areas. The tumor location was considered "erroneous" if its location determined during surgery differed from the location determined by colonoscopy or CT.

Results: Over all, tumor location was accurately determined via colonoscopy in 83/104 cases (79.8%) and erroneously in 21/104 (20.2%) of cases. CT scan accurately localized colon tumors in 52/104 (50.0%) of cases, incorrectly localized tumors in 18/104 (17.3%) of cases, and did not detect known tumors in 34/104 (32.7%) of cases. Of the 21 tumors erroneously located by colonoscopy, 11 (52.4%) were accurately localized by CT scan. The average tumor size for all patients in this study was 5.72 (+/- 3.11) cm. The average size of tumors properly located by colonoscopy and CT was 5.39 (+/- 3.34) cm and 6.79 (+/- 3.48) cm, respectively. The average size of the tumors not detected by CT was 3.98 (+/- 1.75) cm.

Conclusion: CT scanning may be used in concert with colonoscopy to help localize colon tumors.