We evaluated preoperative serum carcinoembryonic antigen (CEA) as a prognostic factor for colorectal cancer patients with normal range of CEA, and determined when surveillance of this marker was useful.
We carried out a retrospective cohort study in CRC patients with normal CEA level (< 5.0 ng/mL) before curative transabdominal resection between January 2005 and June 2012 in Yonsei Cancer Center, and those were followed up with intensive surveillance program. Serum CEA was measured preoperatively in 1,473 patients who underwent surgery, and measured at 3-month intervals for the first 2 postoperative years and at 6-month intervals thereafter up to 5 years.
The 5-year disease-free survival (DFS) rate and overall survival rate were significantly lower in patients with high normal preoperative serum CEA (> 3.0 ng/mL) level (P = 0.033 and 0.025). High normal preoperative serum CEA level was an independent poor prognostic factor for tumor recurrence by multivariate analysis (P = 0.033). In subgroup analysis by tumor–node–metastasis (TNM) stage revealed a lower DFS in patients with high normal preoperative CEA in stage III, while that was not significant in stage I or II. Among patients with a tumor recurrence (N = 190), 52 (27.4%) patients had abnormal serum CEA level (> 5 ng/mL) at recurrence. CEA elevation above normal range at recurrence was observed more frequently in patients with high normal preoperative CEA level. In stage III patients with high normal preoperative serum CEA level, CEA surveillance had a 62.5% positive predictive value (PPV) and an 81.8% negative predictive value (NPV).
High serum CEA level (> 3.0 ng/mL) was an independent prognostic factor for colorectal cancer even in patients with normal range of CEA preoperatively. Postoperative serum CEA surveillance was used most effectively when patients had high normal preoperative serum CEA levels and pathologic stage III.
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All authors have declared no conflicts of interest.