Objective:To determine the clinical serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9), individually and in combination, for the diagnosis of 50 healthy subjects and 150 cases of esophageal, gastric, and colon cancers.
Methods:The sensitivities of the two markers were compared individually and in combination, with specificity set at 100%. Receiver operating characteristic (ROC) curves were plotted.
Results:Serum CEA levels were significantly higher in cancer patients than in the control group. The sensitivity of CEA was determined:in esophageal cancer, sensitivity=28%, negative predictive value (NPV)=61.72%, and AUC=0.742 (SE=0.05), with a significance level of P<0.0001;in gastric cancer, sensitivity=30%, NPV=58.82%, and AUC=0.734 (SE=0.05), with a significance level of P<0.0001;in colon cancer, sensitivity=74%, NPV=79.36%, and AUC=0.856 (SE=0.04), with a significance level of P<0.0001. The sensitivity of CA19-9 was also evaluated:in esophageal cancer, sensitivity=18%, NPV=54.94%, and AUC=0.573 (SE=0.05), with a significance level of P=0.2054. In gastric cancer, sensitivity=42%, NPV=63.29%, and AUC=0.679 (SE=0.05), with a significance level of P<0.0011. In colon cancer, sensitivity=26%, NPV=57.47%, and AUC=0.580 (SE=0.05), with a significance level of P=0.1670. The following were the sensitivities of CEA/CA19-9 combined:in esophageal cancer, sensitivity=42%, NPV=63.29%, SE=0.078 (95%CI:0.0159-0.322);gastric cancer, sensitivity=58%, NPV=70.42%, SE=0.072 (95%CI:-0.0866-0.198);and colon cancer, sensitivity=72%, NPV=78.12%, SE=0.070 (95%CI:0.137-0.415).
Conclusion:CEA exhibited the highest sensitivity for colon cancer, and CA19-9 exhibited the highest sensitivity for gastric cancer. Combined analysis indicated an increase in diagnostic sensitivity in esophageal and gastric cancer compared with that in colon cancer.