Efficacy of routine preoperative computed tomography scans in colon cancer

A retrospective review of 180 patients who underwent surgery for primary colon carcinoma from August 1989 to August 1994 was performed to evaluate the necessity of preoperative CT scans in patients with known colon cancer. Sixty-seven patients had preoperative CT scans. Data were collected to evaluate the ability of the scan to detect hepatic metastases, lymph node involvement, and incidental findings that would possibly alter the planned surgical approach. In this study, CT had a sensitivity and specificity of 75 per cent and 88 per cent, respectively, in detecting hepatic metastases. Only 19 per cent of patients with lymph node involvement were correctly staged with CT scans as having lymphadenopathy. Only 3 of 67 patients had incidental findings on CT scans that ultimately changed the surgical approach. It is apparent that because CT scans detect only 75 per cent of hepatic and 19 per cent of hepatic and lymph node involvement and does not seem to alter the planned approach, it is not justified for routine preoperative evaluation of all patients. We, therefore, recommend a more selective approach to patients suspected of having advanced disease if the surgeon suspects that the information may alter the surgical approach.