PURPOSE: Cytology fails to detect neoplastic cells in approximately 40–50% of malignant pleural effusions, which commonly accompany lung adenocarcinomas. Published reports of the diagnostic sensitivity of various tumor markers are inconsistent. Reports on Her-2/neu in lung adenocarcinoma-associated malignant pleural effusion, for example, differ markedly (72% vs. 10%). In addition, optimal cutoff points have not been determined. To clarify contrasting reports and maximize diagnostic efforts, we evaluated the diagnostic sensitivity, specificity and optimal cutoff points for Her-2/neu, Cyfra 21-1 and carcinoembryonic antigen (CEA) in distinguishing lung adenocarcinoma-associated malignant from benign pleural effusions.
METHODS: Pleural effusion samples were collected from 41 patients with lung adenocarcinoma-associated cytologically malignant effusion, and from 93 with benign conditions including tuberculosis, parapneumonic pleural effusions, congestive heart failure, and liver cirrhosis. We evaluated the diagnostic sensitivity, specificity and cutoff points for tumor markers Her-2/neu, Cyfra 21-1, and CEA to discrimination lung adenocarcinoma-associated malignant from benign pleural effusions.
RESULTS: Her-2/neu, Cyfra 21-1 and CEA vary in their ability to discriminate lung adenocarcinoma-associated malignant pleural effusion from benign effusion, from 79.85%, to 88.81%, to 94.03% respectively. False-positive rates of these markers in various benign effusions are 4.30%, 7.53% and 3.23% respectively. CEA combined with Cyfra 21-1 increases diagnostic sensitivity to 97.6%. The cutoff points for these markers are optimally set at 3.6 ng/mL, 60 ng/mL, and 6.0 ng/mL respectively.
CONCLUSION: Of the three tumor markers evaluated, Her-2/neu has the lowest diagnostic accuracy. Cyfra 21-1 is a useful tumor marker for discriminating malignant from benign pleural effusion. CEA provides the best current diagnostic sensitivity and specificity.
CLINICAL IMPLICATIONS: CEA has both the highest diagnostic accuracy and is a good marker for various groups of pleural effusion only if results are interpreted carefully, particularly in complicated cases. CEA combined with Cyfra 21-1 will increase diagnostic sensitivity in lung adenocarcinoma-associated malignant pleural effusion to near 100%.
DISCLOSURE: Cheng-Chuan Su, No Financial Disclosure Information; No Product/Research Disclosure Information