Evaluation of seven tumour markers in pleural fluid for the diagnosis of malignant effusions

Carcinoembryonic antigen (CEA), carbohydrate antigens 15–3, 19–9 and 72–4 (CA 15–3, CA 19–9 and CA 72–4), cytokeratin 19 fragments (CYFRA 21–1), neuron-specific enolase (NSE) and squamous cell carcinoma antigen (SCC) were evaluated in pleural fluid for the diagnosis of malignant effusions. With a specificity of 99%, determined in a series of 121 benign effusions, the best individual diagnostic sensitivities in the whole series of 215 malignant effusions or in the subgroup of adenocarcinomas were observed with CEA, CA 15–3 and CA 72–4. As expected, a high sensitivity was obtained with SCC in squamous cell carcinomas and with NSE in small-cell lung carcinomas. CYFRA and/or CA 15–3 were frequently increased in mesotheliomas. Discriminant analysis showed that the optimal combination for diagnosis of non-lymphomatous malignant effusions was CEA + CA 15–3 + CYFRA + NSE: sensitivity of 94.4% with an overall specificity of 95%. In malignant effusions with a negative cytology, 83.9% were diagnosed using this association. The association CYFRA + NSE + SCC was able to discriminate adenocarcinomas from small-cell lung cancers. Regarding their sensitivity and their complementarity, CEA, CA 15–3, CYFRA 21–1, NSE and SCC appear to be very useful to improve the diagnosis of malignant pleural effusions.