Preliminary diagnosis should establish whether the presence of fluid in pleural cavity results from a neoplastic process. Our study is an attempt to determine whether lung cancer marker Cyfra 21-1 is capable to distinguish fluid of neoplastic aetiology from other non-neoplastic diseases. The determination of Cyfra 21-1 was performed in 35 patients hospitalised in the Department of Pulmonary Diseases and Tuberculosis, Medical University in Gdańsk, due to the presence of fluid in pleural cavity. The concentration of the marker was determined in serum as well as in the fluid obtained from pleural cavity. Serum Cyfra 21-1 concentrations in patients with lung cancer and other malignant neoplasms were significantly higher when compared with the results obtained from patients with benign neoplasms. As far as fluids from pleural cavity are concerned, Cyfra 21-1 concentrations were high and they did not depend upon the cause of fluid accumulation. Preliminary results allow to speculate that Cyfra 21-1 determined in pleural cavity cannot be considered a marker differentiating between malignant and benign processes. This claim, however, needs to be confirmed in studies on a larger material.

Keywords: cancer, markers, CYFRA 21-1