Diagnostic value of Her-2/neu, Cyfra 21-1, and carcinoembryonic antigen levels in malignant pleural effusions of lung adenocarcinoma

Aims: Cytology fails to detect neoplastic cells in 40-50% of cases of malignant pleural effusion, a condition that frequently accompanies lung adenocarcinoma. Published reports of diagnostic sensitivity of various tumour markers are inconsistent, and optimal cut-off points have not been determined. This study aimed to evaluate the ability of three markers to discriminate lung adenocarcinoma-associated malignant pleural effusion (LAC-MPE) from benign effusion. Methods: Pleural effusion samples were collected from 41 patients with LAC-MPE, and from 93 with various benign conditions. The diagnostic sensitivity and specificity for Her-2/neu, Cyfra 21-1, and carcinoembryonic antigen (CEA) were evaluated. Cut-off points for these markers are optimally set at 3.6μg/L, 60μg/L, and 6.0μg/L, respectively. Results: Her-2/neu, Cyfra 21-1, and CEA vary in their diagnostic accuracy to differentiate LAC-MPE from benign pleural effusion: 79.85%, 88.81%, and 94.03%, respectively. CEA combined with Cyfra 21-1 increases diagnostic sensitivity to 97.6%, with a specificity of 91.4%. Conclusions: With appropriate cut-off points, CEA currently provides the best diagnostic accuracy. Combining CEA with Cyfra 21-1 increases diagnostic sensitivity to nearly 100%. The results of the present study may help clinicians decide whether to obtain a cytological/histological specimen by invasive means to investigate a possible diagnosis of malignancy.