Application of circulating tumor cells detection in chemotherapeutic efficacy evaluation of non-small cell lung cancer

Objective To investigate the value of circulating tumor cells (CTCs) in the evaluation of chemotherapeutic effect in non-small cell lung cancer (NSCLC). Methods A total of 23 cases of patients with NSCLC receiving chemotherapy were enrolled in this study from January 2015 to June 2017 in the First Affiliated Hospital of the Fourth Military Medical University.Venous blood (5 ml) was extracted from 23 patients prior to chemotherapy, 24h before the first, second, and third cycles of chemotherapy, CTCs were analyzed by CanPatrol™.In the meantime, the tumors were monitored by computed tomography at baseline, and 6 weeks after the first cycle of chemotherapy.According to the response evaluation criteria in solid tumors (RECIST), the patients at the time of 6 weeks after the first cycle of chemotherapy were divided into the effective group [partial response (PR)] and the ineffective group [progressive disease (PD) and stable disease (SD)]. Results The effect of chemotherapy was determined according to RECIST at the time of 6 weeks after the first cycle of chemotherapy, among the 23 patients who went under chemotherapy, the outcomes consisted of partial response in 12 cases (52.2%), stable disease in 1 case (4.3%) and progressive disease in 10 cases (43.5%); the effect of chemotherapy was determined according to the changes of CTCs at the time of 6 weeks after the first cycle of chemotherapy too, and the outcomes consisted of complete response and partial response in 13 cases (56.5%), progressive disease in 10 cases (43.5%). As the results of the Fisher′s exact test showed, there were no significant differences between the two methods in the evaluation of curative effect (P=1.0). Spearman correlation analysis showed that the changes of CTCs number at the time of 6 weeks after the first cycle of chemotherapy were correlated with the curative effect (r=0.861, P=0.000). In the effective group, the number of CTCs of patients at the time of 3 weeks [5.5(4.3, 14.0)CTCs/5 ml] and 6 weeks [3.0(1.3, 5.8)CTCs/5 ml] after the first cycle of chemotherapy were lower than that of before chemotherapy [10.5(7.0, 26.3)CTCs/5 ml], the difference was statistically significant (Z=-2.941, -3.065, both P<0.05); conversely, in the ineffective group the number of CTCs of patients at the time of 3 weeks [7.0(3.0, 9.0)CTCs/5 ml] and 6 weeks [11.0(3.0, 13.0)CTCs/5 ml] after the first cycle of chemotherapy were higher than that of before chemotherapy [3.0(2.0, 5.0)CTCs/5 ml], the difference was statistically significant (Z=-2.687, -2.803, both P<0.05). Conclusions In patients with NSCLC, the therapeutic effect can be evaluated in early stage according to the changes of CTCs number in peripheral blood after chemotherapy.CTCs detection may be a useful supplement to the evaluation system of RECIST. Key words: Non-small cell lung cancer; Circulating tumor cells; Chemotherapy; Evaluation