Background: Serum markers have been tested in patients with malignant effusions for their ability to differentiate malignant pleural mesothelioma from other causes. We have assessed three different serum markers and report our findings in a series of patients with different thoracic malignancies and a group of healthy controls.
Methods: A retrospective analysis of 179 patients and 50 healthy controls was performed. Seventy-four patients had a confirmed mesothelioma, and 106 patients had non-small cell lung cancer (NSCLC), 55 had adenocarcinoma. Soluble mesothelin-related protein (SMRP), Cyfra 21.1, and carcino-embrionic antigen (CEA) were tested in serum at time of presentation.
Results: Cyfra 21.1 was the best single marker discriminating healthy from any malignant disease (area under receiver operating characteristics curve (AUC): 0.92; 95% confidence interval (CI): 0.89-0.96). By combining all three markers the discriminatory power improved marginally (AUC: 0.95; CI: 0.93-0.98; p=0.015). The combination of CEA and SMRP was most accurate in differentiating mesothelioma from NSCLC (AUC: 0.94; 95% CI: 0.90-0.97) and could correctly identify 152 of 179 (85%) cases.
Conclusions: By using two serum markers (CEA and SMRP) we were able to discriminate mesothelioma from NSCLC with high sensitivity, while Cyfra 21.1 is useful in the discrimination of normal versus malignancy.