To explore the significance of tumor markers of pleural effusion in the differential diagnosis of benign and malignant pleural effusion in elderly patients.

A retrospective analysis was performed in 300 patients with pleural effusion in Zhejiang Hospital during July 2012 and July 2019, including 142 patients with malignant pleural effusion and 158 patients with benign pleural effusion. Alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 125, CA199, CA153, CA724, soluble cytokeratin 19 fragment (CYFRA 21-1), neuron-specific enolase (NSE), lactate dehydrogenase (LDH) and adenosine deaminase (ADA) in pleural effusion and serum were detected. Non-parametric test was used to compare the difference of the above indexes between the two groups, and receiver operating characteristic (ROC) curve was used to analyze the value of each index in the differential diagnosis of benign and malignant pleural effusion.

CA153, CA199, CA724, CYFRA21-1, CEA, NSE, AFP and LDH levels in pleural effusion were all higher in malignant group than in benign group (Z=7.11, 5.43, 7.71, 6.40, 7.01, 5.82, 6.20, 5.94; P < 0.01). ROC analysis showed the area under the curve (AUC) of AFP, CEA, CA199, CA153, CA724, CYFRA21-1 and NSE of pleural effusion were all greater than the corresponding serum tumor markers. High cut off values of pleural effusion CEA, CA724, CYFRA21-1, CA153, CA199, NSE, CA125 and AFP were set at 7.50 ng/mL, 3.20 U/mL, 103 ng/mL, 35 U/mL, 30 U/mL, 16 ng/mL, 2 880 U/mL, 2.02 ng/mL, respectivelies, the positive predictive values increased, but the sensitivities decreased.

Most tumor markers of pleural effusion are better than serum tumor markers in the differential diagnosis of benign and malignant pleural effusion in elderly patients. The cutoff value can be increased according to the specific situation to assist in the differential diagnosis.