Assessing the prognostic value of carcinoembryonic antigen levels in stage I and II colon cancer

Background: Previous studies have shown that elevated preoperative carcinoembryonic antigen (CEA) levels are associated with worse prognosis in patients with colon cancer. These studies compared the prognosis of patients with elevated versus normal CEA levels. We sought to assess the prognostic role of increasing levels of CEA in stage I and II patients who did not receive adjuvant chemotherapy. Methods: Using the National Cancer Database (2004–2014), we identified 45,449 individuals with stage I and II colon cancer who did not receive adjuvant chemotherapy and had preoperative CEA levels available. We estimated the optimal cut-point of CEA levels to predict survival using the Youden Index. Cox proportional hazards were used to compare individuals with CEA levels above and below the defined cut-point. In a secondary analysis, we examined the prognostic value of stage, age and tumour location. Results: The optimal preoperative CEA cut-point to predict survival was 2.35 ng/mL. The adjusted HR for overall survival among individuals with preoperative CEA levels at or above compared with below 2.35 ng/mL was 1.56 (95% CI, 1.49–1.64). Individuals with CEA levels below 2.35 ng/mL had higher 3-year survival rates compared with those with CEA levels above 2.35 ng/mL (79.7% vs 64.5%, respectively). Conclusions: Preoperative CEA levels at or above 2.35 ng/mL, found within the normal range, may be used to identify stage I and II colon cancer patients harbouring worse prognosis.