Role of cancer ratio (serum LDH/pleural ADA) and carcinoembryonic antigen in diagnosis of malignant pleural effusion

Abstract

Abstract Background Pleural effusion may be malignant or nonmalignant, Cytology has been used in malignant pleural effusion (MPE) diagnosis due to its high specificity. Its sensitivity is about 0.6. Cancer ratio (CR) and carcinoembryonic antigen (CEA) may be used in MPE diagnosis. Aim Evaluate the role of CR and CEA as diagnostic markers of MPE and their role in differentiating different types of MPE. Patients and methods This cross-sectional study included 70 patients with pleural effusion admitted to Chest Department, Kasr Alainy Faculty of Medicine, Cairo University. Thirty-five patients had benign pleural effusions and 35 patients had MPE. Pleural fluid sample obtained from each patient for ADA, CEA, and serum LDH. CR and pleural fluid CEA were compared between patients with MPE and those with benign effusion. Results CR was statistically significantly higher in the malignant group (mean 23.66 ± 7.75) compared with benign group (mean 14.47 ± 11.42) with P value less than 0.001. CR cut-off value was 19.79, the sensitivity and specificity were 74.3 and 82.9%, respectively. Pleural fluid CEA had higher levels in malignant group (mean 104.78 ± 262.7) compared with benign group (mean 2.08 ± 2.49) with P value less than 0.001. The cut-off value of CEA was 3.4 U/l with sensitivity 74.3% and specificity 94.3%. Pleural fluid CEA was significantly higher in metastatic adenocarcinoma (mean 154.58 ± 314.53) compared with other types of malignancy (mean 9.34 ± 17.98) with P value less than 0.001. Conclusion CR and CEA could be used together as simple screening tests in cytology negative MPE with high specificity and sensitivity. CEA was significantly higher in metastatic adenocarcinoma compared with other types of malignancy and could be used to differentiate different types of MPE.