Purpose: The aim of this study was to assess the significance of the correlation among tissue carcinoembryonic antigen (CEA) expression with serum CEA (sCEA) levels and long-term survival to highlight the clinical prognostic significance of tissue CEA expression in gastric cancer patients.
Methods: Immunohistological method and radioimmunoassay were used to assess tissue and sCEA expression, respectively. Univariate and multivariate analyses were performed to determine correlations, and the Kaplan-Meier method was used to investigate the prognostic significance.
Results: Our results demonstrate that tissue CEA in gastric cancer is significantly correlated with preoperative sCEA levels (p = 0.031), depth of invasion (p = 0.001), lymph node metastasis (p < 0.001), distant metastasis (p = 0.001), and TNM staging (p < 0.001). The 5-year survival rates were 67.6, 53.9, and 40.1 % for negatively, moderately, and intensely positively stained tissues (p < 0.001), and 57.0 and 37.9 % for serum with normal and elevated CEA expression (p = 0.031). Multivariate analysis revealed that tissue CEA can be considered an independent prognostic factor. Further analysis illustrated that patients with negative expression in both tissue and serum had better prognosis compared with those positively expressing CEA in both tissue and serum and/or those positively expressing CEA in either tissue or serum (p < 0.001). Our results also demonstrated that patients with negative tissue CEA staining and elevated sCEA expression had a better 5-year survival.
Conclusion: Tissue CEA expression in gastric cancer is directly correlated with sCEA levels and long-term prognosis. Thus, tissue CEA expression can be considered as a useful biomarker to improve the interpretation of sCEA levels in predicting long-term survival.