High preoperative serum CA 19-9 levels can predict poor oncologic outcomes in colorectal cancer patients on propensity score analysis

Purpose: The purpose of this study is to evaluate the prognostic value of preoperative serum CA 19-9 levels in colorectal cancer patients. Methods: Between 2008 and 2011, 4,794 consecutive patients who underwent curative resection for colorectal cancer were analyzed. These patients were classified into 2 groups according to preoperative CA 19-9 (high CA 19-9: ≥37 ng/mL, n = 440; normal CA 19-9: <37 ng/mL, n = 4,354). We used 1:20 propensity score matching to adjust for potential baseline confounders between groups. Results: After matching, 424 patients (10.5%) among 4,021 patients with colorectal cancer showed a high pre-CA 19-9 level (≥37 ng/mL). There were no significant differences between these 2 groups in age, sex, preoperative CEA level, or T, N, and M stage after matching. Of the 424 patients with high pre-CA 19-9, 141 (33.3%) exhibited cancer recurrence more frequently than patients with normal preoperative CA 19-9 (18.5%). Patients with an elevated preoperative CA 19-9 level showed significantly poorer survival than those with normal levels. The 5-year overall survival rate was 79.7% in the high preoperative CA 19-9 group and 91.9% in the normal preoperative CA 19-9 group (P < 0.001). The 5-year disease-free survival rate was 70.2% in the high preoperative CA 19-9 group and 82.7% in the normal preoperative CA 19-9 group (P < 0.001). Conclusion: Patients with an elevated preoperative CA 19-9 level in colorectal cancer have a significantly poorer prognosis than those with normal levels of CA 19-9. We therefore suggest preoperative CA 19-9 level can be used as an additional prognostic indicator of poor outcomes in colorectal cancer.