Tissue carcinoembryonic antigen as a superior independent prognostic factor for colorectal cancer over serum CEA: a retrospective cohort study

We explored the relationships between tissue carcinoembryonic antigen (t-CEA) and serum CEA (s-CEA) and further pursued their association with long-term survival among postoperative colorectal cancer (CRC) patients. All patients underwent determination of s-CEA levels and t-CEA expression. Pearson correlation analysis was performed to quantify the interactions between two variables. Kaplan-Meier survival analysis and time-dependent receiver operating characteristic (ROC) analyses were performed. Prognostic factors were subjected to analysis using multivariable Cox regression to form prognostic nomograms. The results showed the positive rate of t-CEA overexpression recorded at 90.96%. No significant correlation was shown between the two variables. CRC patients with high t-CEA expression revealed a significantly poorer overall survival (OS) and progression-free survival (PFS). In unadjusted Kaplan-Meier survival analyses, elevated s-CEA levels were associated with significantly poorer PFS (p = 0.033) but not OS (p = 0.077). Crucially, multivariable Cox proportional hazards regression confirmed that high t-CEA expression, rather than s-CEA, served as a robust independent prognostic factor for both OS (HR = 2.887, p = 0.017) and PFS (HR = 2.500, p = 0.002). Nomograms comprising t-CEA were constructed with superior utility in predicting the survival probability of CRC patients. To conclude, our study demonstrates the superior prognostic value of t-CEA as an independent prognostic factor for CRC compared to s-CEA.