Background: In this study, we aimed to investigate the preoperative serum carcinoembryonic antigen (CEA) in the diagnosis of positive lymph node metastasis (LNM), and to evaluated the relationship between CEA and survival in patients with locally advanced gastric cancer (LAGC).
Methods: The significance of the preoperative serum CEA level for the diagnose of LAGC and prediction of LNM was determined using the receiver operating characteristic (ROC) curve. The areas under the ROC of CEA were compared with those of other tumor markers or imaging examination including CT and MRI. Logistic regression was utilized to identify the risk factors predicting positive LNM. Independent prognosis factors were evaluated using univariate and multivariate COX regression analyses.
Results: The ROC curves showed that the AUCs of CEA, CA199, and CA125 for diagnosing LAGC were 0.727, 0.594, and 0.566. When used to predict LNM, the AUC of CEA, CA199 and CA125 were 0.696, 0.531, and 0.588. Logistic regression analysis demonstrated that preoperative serum CEA were significantly associated with positive LNM. On combining imaging examination with CEA, the sensitivity and specificity were 85.3 and 79.4%, respectively, with the AUC equal to 0.853. The combination of CEA and imaging examination preformed the highest levels of AUC and sensitivity for diagnosing LNM, which is significantly higher than using either of them alone. Although patients with abnormal CEA have a poor prognosis, two models of multivariate analysis showed that CEA was not the independent prognosis factor for survival.
Conclusions: CEA can be used to diagnose gastric cancer and determine whether it has LNM. Moreover, combined with CEA could improve the diagnostic sensitivity of imaging examination for lymph node involvement.
Keywords: Carcinoembryonic antigen; Gastric cancer; Imaging examination; Lymph node metastasis; Prognosis.