CEA, CA-15-3 AND CYFRA-21-1 IN SERUM AND PLEURAL FLUID OF PATIENTS WITH PLEURAL EFFUSIONS

The role of tumour marker assays in differentiating malignant from ben ign pleural effusions is not yet clear, This study was designed to pro spectively assess the individual and combined diagnostic utility of th ree tumour markers in patients with pleural effusion. Pleural and seru m levels of carcinoembryonic antigen (CEA), carbohydrate antigen 15-3 (CA 15-3) and cytokeratin 19 fragment (CYFRA 21-1) were determined in 115 patients with pleural effusions (42 malignant and 73 benign), The diagnostic utility of each tumour marker was assessed using accuracy t o determine the optimal cut-off point, whilst a logistic regression mo del was used to obtain the optimal combined test. In serum, every mark er showed an individual high specificity (over 97%) for malignancy, Th e sensitivity of CEA, CA 15-3 and CYFRA 21-1 was 36, 48 and 31%, respe ctively, In patients without renal failure, the sensitivity of CYFRA 2 1-1 rose to 53%, while those of CEA and CA 15-3 remained almost unchan ged, In pleural fluid, CYFRA 21-1 showed low sensitivity (32%) and spe cificity (82%), while CEA showed the highest sensitivity (57%), Exclud ing patients with renal failure, the combined determination in serum o f CEA, CA 15-3 and CYFRA 21-1 has a high accuracy (88%), similar to th at for CEA plus CA 15-3 in pleural fluid (87%). We conclude that CYFRA 21-1 is useless in pleural fluid and should not be used in serum for patients with renal failure, The combined determination of CEA, CA 15- 3 and CYFRA 21-1 in serum may obviate its determination in pleural flu id.