[Clinical value of classified detection of circulating tumor cells in peripheral blood of NSCLC patients].

ABSTRACT

OBJECTIVE: To investigate the clinical value of detection of circulating tumor cells (CTCs) classified by epithelial cell adhesion molecule (EpCAM) in peripheral blood of patients with non-small cell lung cancer (NSCLC). METHODS: Peripheral blood samples (7.5 ml each time) were collected from 47 NSCLC patients. Among them, blood samples were collected at the end of each therapy-cycle in three patients for longitudinal monitoring of CTCs. CTCs were enriched by the depletion of leucocytes using a magnetic bead separation technique, stained with EpCAM, cytokeratin 7/8 and their isotypic control antibodies, respectively, and then identified and counted by multi-parameter flow cytometry. RESULTS: In the blood samples from 47 patients, EpCAM-positive CTCs were detected in 64.3%(9/14), 40.0%(4/10) and 43.5%(10/23) of patients in stages Ⅰ-Ⅱ, Ⅲ and Ⅳ, respectively. EpCAM-negative CTCs were detected in 78.6%(11/14), 90.0%(9/10) and 91.3%(21/23) of patients in stage Ⅰ-Ⅱ, Ⅲ, and Ⅳ, respectively. The total detection rates of EpCAM-positive and EpCAM-negative CTCs were 48.9%(23/47) and 87.2%(41/47), respectively, showing a statistically significant difference between them (P<0.001). According to the stage of the cancer, there was a significant difference between the detection rates of the two types of CTCs in patients of stage Ⅳ(P=0.001), but not in stage Ⅰ-Ⅱ and Ⅲ (P>0.05). The number of EpCAM-negative CTCs was significantly higher than that of EpCAM-positive CTCs in all stages (P<0.05). The frequency of patients with the percentage of EpCAM-negative CTCs >90% was significantly higher in stage Ⅳ patients than that in stage Ⅰ-Ⅱ cases (P=0.030), while the frequency of patients with the percentage of EpCAM-negative CTCs between 50%~90% was significantly lower in the stage Ⅳ than that in the stage Ⅰ-Ⅱ patients (P=0.001). The treatment of most patients with EpCAM-negative CTCs >50% showed to be ineffective (P=0.033). CONCLUSION: Detection of CTCs classified by EpCAM in peripheral blood is helpful in evaluating the distant metastasis and treatment effectiveness of NSCLC patients.