Combination of D-dimer and carcinoembryonic antigen levels as a predictive and prognostic biomarker in advanced colorectal cancer patients.

In view of the controversial findings on the utility of D-dimer and carcinoembryonic antigen (CEA) as biomarkers in advanced colorectal cancer (CRC), we evaluated the predictive and prognostic value of the D-dimer and CEA levels in unresectable advanced CRC patients treated with first-line chemotherapy. A total of 57 previously untreated patients with advanced CRC were enrolled. We assessed both plasma D-dimer and CEA levels at the start (D1 and CEA1) and after two cycles (D2 and CEA2) of chemotherapy. Based on the respective optimal cut-off values of 0.8 and 5.0 ng/mL for D1 and CEA1, respectively, patients were divided into low and high D-dimer or CEA groups. The results show that D1 and CEA1 levels were correlated (r = 0.392, P = 0.003). Mean CEA2 was reduced by 26.24 ng/mL in patients with partial response and stable disease and increased by 165.95 ng/mL in patients with progressive disease relative to the CEA1 level (P < 0.001). However, no correlation was evident between changes in the D-dimer levels and chemotherapy response (P = 0.441). The overall survival (OS) of patients with high D1 was shorter than that of patients with low D1 (median OS, 16 vs 29 months, P = 0.009). Multivariate analyses further demonstrated that D1 (P = 0.042) and chemotherapy response (P = 0.016), but not CEA, were independent prognostic factors for OS in advanced CRC. Taken together, our result found that changes in CEA levels may serve as a predictive biomarker of the chemotherapy response and baseline D-dimer levels as a prognostic biomarker of OS in patients with advanced CRC.