Postoperative surveillance of colorectal cancer according to risk category.

Over about a 7-year period, 138 colorectal cancer patients undergoing potentially curative surgery were prospectively entered into postoperative surveillance programs that differed according to risk category. Of the 138 patients, 28 (20%) have been lost to follow-up. Of the 110 remaining patients, thirty (27.3%) were classified as low risk cases since they had stage A-B1, well differentiated tumors (G1) primary tumors with preoperative CEA values of less than 7.5 ng/ml (group 1) and the remaining 80 patients (72.7%) were considered high risk cases (group 2). Overall 5 year survival was 64.5%; group 1 patients had a significantly better 5-year survival rate (90%) as compared to group 2 patients (55%) (p less than 0.01). Of the 20 asymptomatic patients with distant metastases only 4 (20%) underwent potentially curative surgery, whereas of 13 asymptomatic patients who recurred locally surgery was undertaken in 9 (69%) (p less than 0.05). At 5 years from the diagnosis of local recurrence, 5 of 11 patients (45.4%) who underwent curative second-look surgery are still alive. The survival of low risk patients was not negatively influenced by less frequent follow-up. Endoscopy and echotomograms were the most useful diagnostic tools in detecting early local anastomotic recurrence and hepatic metastases, respectively. Individualized follow-up programs for various risk categories of colorectal cancer patients are recommended.