Clinical study of circulating tumor cells in monitoring the efficacy of neoadjuvant immunotherapy for non-small cell lung cancer

Abstract

Objective: To investigate the changes of CTCs and the correlation between the changes of CTCs and the clinical efficacy of neoadjuvant immunotherapy for non-small cell lung cancer (NSCLC). Methods: A retrospective case-control study was conducted to collect the data of 23 patients with NSCLC who received neoadjuvant immunotherapy in the Third Xiangya Hospital from June 2018 to December 2019. They were 35-76 years old with a median age of 52 years old, including 13 male patients and 10 female patients. The CTCs value, evaluation results from response evaluation criteria in solid tumor (RECIST) and major pathological response were evaluated before treatment, after neoadjuvant immunotherapy and after operation. Mann Whitney U test was used for the comparison between the two groups, Wilcoxon test was used for the comparison of association samples, and Kruskal Wallis test was used for the comparison between multiple samples. Results: The CTCs value was positively correlated with tumor progression, that the CTCs value of ⅡB group, ⅢA group and ⅢB group was 10.69 (3.87) FU/3 ml, 12.90 (2.24) FU/3 ml and 16.04 (3.43) FU/3 ml, and the difference was statistically significant (χ2=7.829, P=0.020). Then CTCs decreased to 7.60(4.79) FU/3 ml significantly (Z=4.197,P=0.000), and decreased to 6.22(2.80) FU/3 ml significantly again after surgery(Z=-2.950,P=0.005). In RECIST results, the CTCs value of CR group, PR group and SD group was 12.90(3.79)FU/3 ml, 12.52(3.96) FU/3 ml and 13.58(5.11) FU/3 ml,and no significant difference before treatment (χ²=1.806, P=0.405). After neoadjuvant immunotherapy, the CTCs of CR group decreased to 6.22(3.87) FU/3 ml significantly (Z=-4.950, P= 0.000), and also PR group to7.32(4.31) FU/3 ml (Z=-3.180, P=0.001) or SD group to (Z=-2.023, P=0.043). There was no significant difference between CR group and PR group (Z=-0.838, P=0.402), but significant difference between SD group and CR/PR group (Z=-1.922, P=0.050). After operation, the CTCs of CR, PR and SD group decreased to 6.09(3.43) FU/3 ml, 6.40(1.82) FU/3 ml and 9.20(5.16) FU/3 ml,and there was no significant difference to preparation in CR group and PR group, but significant difference in SD group (Z=-2.023, P=0.043). There was no significant difference between CR group and PR group (Z=-1.134, P=0.257), but significant difference between SD group and CR/PR group (Z=-1.624, P=0.014). Before treatment,CTCs of MPR group and non-MPR group were 11.98(4.14) FU/3 ml and 13.54(4.76) FU/3 ml,and there was no significant difference between them (Z=-1.354, P=0.176). After neoadjuvant immunotherapy, the CTCs of MPR group decreased to 6.36(2.65) FU/3 ml significantly (Z=-2.934, P=0.001) and also in non-MPR group to 10.88(2.80) FU/3 ml (Z=-2.840, P=0.003); but there was significant difference between MPR group and non-MPR group (Z=-3.693, P=0.000), and also the change of CTCs between two groups (Z=-2.770, P=0.006). After operation, the CTCs of MPR group decreased to 5.40(1.33) FU/3 ml insignificantly (Z=-0.533, P=0.594) but significantly to 7.05(3.80) FU/3 ml in non-MPR group (Z=-2.734, P=0.030), and significant difference between them (Z=-1.900, P=0.011). Conclusion: The value of CTCs is negatively correlated with the efficacy (RECIST and MPR) of neoadjuvant immunotherapy for NSCLC, which can be used for clinical efficacy evaluation of neoadjuvant immunotherapy.