Diagnostic utility of CYFRA 21-1 in malignant pleural effusion

The diagnostic utility of the tumour marker CYFRA 21-1 in malignant pleural effusion is not yet clear. This study was designed to evaluate the diagnostic utility of serum and pleural fluid CYFRA 21-1 in malignant pleural effusion.The validity of serum and pleural fluid CYFRA 21-1 was determined in 62 patients with exudative pleural effusion (27 malignant and 35 benign). The diagnosis of malignant pleural effusion was defined by cytological or histological results.A statistically significant difference between the geometric means of CYFRA 21-1 levels in pleural fluid of benign and malignant aetiologies was observed (11.2 vs 63.3 ng/mL, P < 0.0001). In addition, there was a significant difference in the serum levels (0.95 vs 5.55 ng/mL, P < 0.0001). The sensitivity and specificity of pleural fluid CYFRA 21-1 in malignant pleural effusion, at the cut-off value of 55 ng/mL, was 74.1% and 97.1%, respectively. The sensitivity and specificity of serum CYFRA 21-1, at the cut-off value of 2.5 ng/mL, was 81.5% and 97.1%, respectively. Using a combination of serum and pleural fluid CYFRA 21-1 level, the sensitivity increased to 88.9%.Serum and pleural fluid CYFRA 21-1 are useful as measures in differentiating malignant from benign pleural effusion.