Postoperative carcinoembryonic antigen (CEA) levels predict outcomes after resection of colorectal cancer in patients with normal preoperative CEA levels

BACKGROUND: Carcinoembryonic antigen (CEA) is a cancer biomarker used in colorectal cancer (CRC) for tumor screening and outcome prediction. However it is still lack of sensitivity and specificity in general population. The present study aimed to investigate the clinical significance of CEA in patients with normal preoperative CEA levels. METHODS: Ninety-four patients were included who received surgery and developed an elevated CEA level postoperatively. They were divided into group A1 and A2 according to the peak CEA level (whether more than 10 ng/mL); group B1 and B2 according to CEA variation (whether reached a normal level at least once). The association between postoperative CEA and overall survival (OS), and disease-free survival (DFS) were analyzed using Kaplan-Meier method and Cox’s proportional hazards regression model. RESULTS: The median follow-up time was 38 months. Patients in Group A2 and Group B2 had greater opportunities for recurrence and metastasis (P<0.05) compared to Group A1 and Group B1. Cox regression analysis revealed that high CEA levels and consistently elevated CEA levels were significantly associated with worse OS and DFS. Furthermore, patients with p-stage II in group A2 had worse OS than patients with p-stage III in group A1. The same result was detected when comparing group B2 and B1. CONCLUSIONS: Among patients with an initially normal CEA level, postoperative CEA level and variation could be effective markers for tumor progression assessment. TNM stage, combined with CEA level might be more accurate in prognostic prediction.