Use of the preoperative levels of CEA in patients with colorectal cancer

Abstract

Background/aims: Preoperative carcinoembryonic antigen has been considered useful as a prognostic factor and recurrence indicator of colorectal neoplasms. However, its diagnostic ability related to some parameters such as resectability or tumor staging has been less studied. The aim of this study was to evaluate the use of this marker as a diagnostic test for these parameters of colorectal cancer. Methodology: In a sample of 283 patients operated on for colorectal carcinoma data were retrospectively recorded corresponding to preoperative carcinoembryonic antigen, type of surgery performed (curative vs. non-curative), tumor intramural spread, lymph node involvement, distant metastasis, TNM stage, tumoral differentiation, survival time and survival time free of disease. Bivariate analysis between carcinoembryonic antigen and the rest of the parameters was performed. Also, the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy (efficiency) of the marker considered as a diagnostic test, were analyzed in relation to the tumoral resectability and tumoral spread. Results: Preoperative level of serum carcinoembryonic antigen was statistically significantly associated with type of surgery performed (p < 0.001); tumoral intramural spread (p = 0.001); lymph node involvement (p < 0.001); presence of distant metastasis (p < 0.001); TNM staging (p < 0.001); overall survival period (p < 0.001) and disease-free survival time (p = 0.04). There was no relation between carcinoembryonic antigen and the degree of tumoral differentiation. The carcinoembryonic antigen's greatest sensitivity corresponded with the prediction for the type of the surgery performed and with the existence of distant metastasis, 80% and 70.9%, respectively. The negative predictive value was also high (> 90% in both cases). When considering the intramural spread, the specificity was 82% and its positive predictive value 93.1%. Conclusions: Preoperative levels of serum carcinoembryonic antigen, considered as a diagnostic test, are useful as predictors of resectability and tumor spread in colorectal carcinoma.