Use of tumor markers for differential diagnosis of mesothelioma and secondary pleural malignancies

Study objective: The aim of the study was to assess diagnosis value of tumo r markers for differential diagnosis between mesothelioma and other pleural tumors. Design and methods: Prospective study of 85 patients attending our hospital with malignant pleural effusion. The diagnostic approach involved routine pleurocentesis followed by pleural needle. When precise diagnosis was not a chieved, thoracoscopy with pleural biopsies was performed. Carcinoembryonic antigen (CEA), hyaluronic acid, tissue polypeptide antigen and cyfra 21 to 1 were measured in serum and pleural fluid. Results: By using receiver operating characteristics curves and area under curves, the best diagnostic characteristics were obtained with pleural and serum CEA concentrations. The area under the curve was larger for pleural A CE than for serum ACE. The sensitivity and specificity of a pleural CEA lev el exceeding 3 ng/mL for ruling out the diagnosis of mesothelioma were 100% and 77%, respectively. Conclusion: A CEA level above 3 ng/mL in pleural fluid eliminated the diagn osis of mesothelioma, whereas the other markers were not sufficiently discr iminant. However, despite a negative predictive value of 100% at a cutoff o f 3 ng/mL, CEA assay in pleural fluid only avoids a small number of diagnos tic thoracoscopies. Copyright (C) 2000 The Canadian Society of Clinical Che mists.