The Significance of Monitoring Serum Carcinoembryonic Antigen in the Colorectal Cancer after Curative Resection

ABSTRACT

BACKGROUND/AIM: Serial measurement of serum carcinoembryonic antigen was assessed to define its significance and to determine the adequacy in detecting recurrence after curative resection for colorectal cancer. METHODS: Six hundred forty-five patients with colorectal cancer underwent curative resection were included. The median follow-up period was 49 months (range, 24~94 months). Serum CEA was analyzed in accordance with location, histologic differentiation, stage of the tumor, recurrence and survival. RESULTS: The incidence of elevated preoperative serum CEA (> 6 ng/ml) was correlated with tumor stage (stage I vs. II, P=0.01; stage II vs. III, P=0.0001). Fifty five patients among 87 patients with recurrence (63.2%) had concomitant elevation of serum CEA, whereas 32 of 558 patients (5.7%) without recurrence showed a false-positive result. Measurement of serum CEA was more sensitive in patients with elevated preoperative serum CEA and liver metastases than in patients without elevated preoperative serum CEA and local recurrence (P=0.0397). The leading time of serum CEA between the first elevated serum CEA and the identification of recurrence was 3.5 months (range, 1~12 month). Tumor stage and preoperative serum CEA level were found to be significant prognostic variables by multivariate analysis. The overall 5-year survival rate in the normal preoperative serum CEA and the elevated group were 76% and 64% respectively (P=0.00019). CONCLUSION: Serum CEA seemed to be closely correlated with survival and to be an useful tool to detect recurrence after curative resection for colorectal cancer. The appropriate measurement of serum CEA might be suggested in stage II and III postoperatively: every three month for two years, every 6 month for succeeding 2 years, and annually thereafter. Monitoring of serum CEA in stage I could be individualized by preoperative serum CEA and clinical course.