DIAGNOSTIC-VALUE OF CYTOKERATIN FRAGMENT-19 (CYFRA 21-1) IN BRONCHOALVEOLAR LAVAGE FLUID IN LUNG-CANCER

The aim of this study was to evaluate the diagnostic value of a new tu mour marker, cytokeratin fragment 19 (CYFRA 21-1), in bronchoalveolar lavage fluid (BALF) for the diagnosis of lung cancer. The cross-sectio nal study included 36 patients with lung cancer, 19 with benign lung d iseases and 13 control subjects. In the group with cancer, BAL was per formed in the cancer-involved lung and in the opposite lung. Results i n BALF were expressed both as absolute concentrations (ng ml(-1)) and referred to total protein (TP) (ng mg(-1) TP), and results in plasma w ere expressed in ng ml(-1). In BALF, there was no significant differen ce between cancer and control groups. Using the 95th percentile of lev els obtained in benign lung disease in BALF (specificity 95%) as the c ut-off point, the sensitivity of CYFRA 21-1 was 13%. Positive and nega tive predictive values (PPV and NPV) at different pretest probabilitie s, and positive and negative gains were obtained applying a Bayesian a nalysis. Results showed low positive gains for PPV (maximal increase o f 22%) and almost none for NPV (negative gains <5%). In plasma, CYFRA 21-1 provided a sensitivity of 65%. The combination of BALF and plasma tumour marker levels showed a sensitivity of 69%. Therefore, measurem ent of CYFRA 21-1 in BALF has poor diagnostic value in lung cancer.