Diagnostic value of cytokeratin fragment 19 (CYFRA 21-1) in bronchoalveolar lavage fluid in lung cancer

AbstractThe aim of this study was to evaluate the diagnostic value of a new tumour marker, cytokeratin fragment 19 (CYFRA 21-1), in bronchoalveolar lavage fluid (BALF) for the diagnosis of lung cancer. The cross-sectional study included 36 patients with lung cancer, 19 with benign lung diseases and 13 control subjects. In the group with cancer, BAL was performed in the cancer-involved lung and in the opposite lung. Results in BALF were expressed both as absolute concentrations (ng ml−1) and referred to total protein (TP) (ng mg−1 TP), and results in plasma were expressed in ng ml−1. In BALF, there was no significant difference between cancer and control groups. Using the 95th percentile of levels obtained in benign lung disease in BALF (specificity 95%) as the cut-off point, the sensitivity of CYFRA 21-1 was 13%. Positive and negative predictive values (PPV and NPV) at different pretest probabilities, and positive and negative gains were obtained applying a Bayesian analysis. Results showed low positive gains for PPV (maximal increase of 22%) and almost none for NPV (negative gains