Diagnostic value of tumor antigens in malignant pleural effusion: a meta-analysis

The diagnostic value of tumor markers, carcinoembryonic antigen (CEA), cancer antigen (CA) 15-3, CA 19-9, CA 125, cytokeratin fragment (CYFRA), and neuron-specific enolase (NSE) in pleural fluid to differentiate between benign and malignant pleural effusion (MPE) has not yet been clearly established. A review of English language studies using human subjects was performed. Sensitivity and specificity values of the chosen tumor markers were pooled using a random effects model to generate hierarchical summary receiver operator curves to determine the diagnostic performance of each tumor marker. A total of 49 studies were included in the final analysis. Pooled sensitivity and specificity values for chosen tumor markers for diagnosing MPE are as follows: CEA, 0.549 and 0.962; CA 15-3, 0.507 and 0.983; CA 19-9, 0.376 and 0.980; CA 125, 0.575 and 0.928; CYFRA, 0.625 and 0.932; NSE, 0.613 and 0.884. The use of individual tumor markers in diagnosing MPE has many benefits (cost, invasiveness, and so forth). Although these tumor markers exhibit high specificity, the low sensitivity of each marker limits the diagnostic value. We conclude that tumor markers used individually are of insufficient diagnostic accuracy for clinical use. Tumor markers used in various combinations or from serum may have some potential worth further investigation.