Objective: The presence of malignant pleural effusion in lung cancer refers to an advanced stage and the survive of these patients after surgical resection is unfortunately poor. The nature of pleural effusion should be clarified in lung cancer as it is important for accurate diagnosis and an appropriate treatment protocol. However, diagnostic yield of cytological examination of pleural fluids may sometimes be limited in clinical practice so more sensitive diagnostic methods are needed. Telomerase has been proposed to be a diagnostic marker for malignancy in body cavity fluids in various papers. In this study, our aim is to evaluate the diagnostic efficacy of telomerase activity in pleural effusions of patients with lung cancer and to compare with the results of cytologic examination.

Patients and Method: A total of 33 pleural effusion samples were collected from patients with lung cancer (n=18) and with benign disease (n=15) in whom the diagnosis was confirmed with cytological and/or histological examinations. Telomerase activity was determined with PCR-based TRAP (The telomeric repeat amplification protocol) assay.

Results: The sensitivity and specificity of telomerase activity were found to be 77.8%, and 80.0%, respectively. Diagnostic accuracy of telomerase activity was 78.7%. The sensitivity rate of cytological examination when combined with telomerase activity (88.9%) was observed to be significantly greater than that of cytological examination alone (66.7%) (p = 0.046).

Conclusion: Detection of telomerase activity in pleural effusion is a reliable and effective diagnostic method and may be used as an adjunct to cytological examination in lung cancer.