Fig. 2

ROC curve analyses of the use of CTC, CEA and imaging examinations to differentiate patients with NSCLC from those with benign lung disease. (A) Combining CTC with nodule density, nodule size, nodule location, and CEA significantly improved the sensitivity and specificity of the diagnosis. Nodular density, CEA and CTC are independent prognostic factors. (B) The relationship between CTCs and CEA values in upper lobe, subsolid and ≥ 8-mm nodules, using the CTC threshold of 12 units/6 ml and the CEA threshold of 1.78 ng/ml