Clinical Value of Circulating Tumor Cell in the Differential Diagnosis of Solitary Pulmonary Nodule

Objective To evaluate the application value of circulating tumor cell ( CTC ) in the differential diagnosis of solitary pulmonary nodule ( SPN ) . Methods Peripheral blood samples were collected from 134 patients with solitary pulmonary nodule in Shanghai Chest Hospital from September 2013 to January 2015, including 80 patients with malignant nodule and 54 with benign nodule.CTC levels of the above subjects were detected by ligand-targeted polymerase chain reaction ( LT-PCR ) assay, and serum carcinoembryonic antigen ( CEA ) and cytokeratin 19 fragment ( CYFRA21-1 ) were detected by flow fluorescence assay.Results By Mann-Whitney U Test, the CTC levels of malignant SPN patients [11.06 (8.77-14.41)units/3 ml] were significantly higher than those of benign SPN patients [6.65(4.49 -7.84)units/3 ml] (Z=-6.217,P<0.001).The sensitivity and specificity of differential diagnosis of SPN for CTC were 80%(64/80) and 85%(46/54) respectively.According to the diameter of SPN, the patients were divided into three groups to evaluate the diagnostic value of CTC in SPN with different size .For SPN with diameter less than 8 mm, the sensitivity and specificity of CTC were 6/9 and 4/5 respectively .For SPN with diameter between 8 mm and 20 mm, the sensitivity and specificity of CTC were 83%(35/42) and 85%(29/34).For SPN with diameter greater than 20 mm, the sensitivity and specificity of CTC were 79%(23/29) and 13/15.Conclusion Comparing with the traditional tumor markers, CTC could provide more clinical value in the differential diagnosis of solitary pulmonary nodule .