The role of carcinoembryonic antigen as a predictor of the need for preoperative computed tomography in colon cancer patients.

A retrospective study of 117 patients with the diagnosis of colon cancer was performed to evaluate the clinical utility of the preoperative computed tomography (CT) scan and to assess the role of carcinoembryonic antigen (CEA) as a predictor of the need for CT scan in colon cancer patients. Forty-nine patients had a CT scan that altered their treatment. One hundred per cent of stage IV patients versus only 26.5 per cent of stage I, II, and III patients had their operative and/or treatment planning altered by the preoperative CT. The sensitivity of CT scan in predicting metastatic disease was 90.3 per cent. All patients with stage IV disease had an abnormal CEA (>3 ng/mL). There was 89.7 per cent of stage IV patients who had a CEA twice that of normal or above. By using a CEA level of 3.1 ng/mL or above as a prerequisite for preoperative tomography, 34 nonmetastatic patients would not have had preoperative CT scans. Using a prerequisite of 6.1 ng/mL or above, 49 nonmetastatic patients would not have had a preoperative CT scan, and 90 per cent of the stage IV patients would have been imaged. We recommend obtaining a preoperative CT scan on those patients with a CEA value twice that of normal or greater.