Levels of tumor markers in pleural effusions may help to establish the diagnosis of pleural malignancy, but the precise diagnostic value of each marker remains unclear. The aim of this study was to assess the diagnostic value of five common pleural fluid tumor markers, carcinoembryonic antigen (CEA), cytokeratin fragment (CYFRA) 21-1, cancer antigen (CA) 15-3, CA 19-9, and CA 125, and to review the literature from the past 15 years. Pleural fluid samples were collected prospectively from 116 patients and assayed for CEA, CYFRA 21-1, CA 15-3, CA 19-9, and CA 125 levels. A MEDLINE search of the English-language literature from the past 15 years was also done. Effusions were classified as benign or malignant on the basis of their definitive pathologic or cytologic diagnoses. The levels of all pleural tumor markers were statistically significantly higher in the malignant group than in the benign group. The marker with the highest accuracy was CEA (85.3%); CA 15-3, CYFRA 21-1, and CA 19-9 had similar accuracies (75.2%, 72.4%, and 71.5%, respectively), and CA 125 had the lowest accuracy (40.5%). On univariate analysis, tumor-marker combinations did not result in a greater accuracy than that of CEA alone. On multivariate logistic regression, CA 15-3 and CYFRA 21-1 were significant predictors of malignancy. Among the nine reports in the literature comparing 11 different tumor markers, CEA, CA 15-3, and CYFRA 21-1 yielded the best results. We conclude that pleural fluid analysis should include CEA for the diagnosis of malignancy. CA 15-3 and CYFRA 21-1 may serve as alternative options.
- Pleural effusion
- Tumor marker