Detection And Clinical Significance Of Circulating Tumor Cells In Advanced Colorectal Cancer

Purpose To evaluate the effectiveness of immunomagnetic bead negative enrichment technique combined with immunofluorescence in situ hybridization technologies in the detection of peripheral blood circulating tumor cells(CTCs)in advanced colorectal cancer(CRC)patients.To evaluate the prognostic value of CTCs in CRC patients during chemotherapy course.Methods Totally 121 newly-acquired and histopathologically confirmed CRC patients in the Shanghai Ninth People's Hospital affiliated to Shanghai Jiao Tong University School of Medicine,from January 2016 to September 2017 were enrolled according to the inclusion and exclusion criteria.Venous blood samples of 7.5 m L was collected from upper limb in healthy side of patients during 2-6 cycles of chemotherapy,and immunomagnetic bead negative enrichment technique combined with immunofluorescence in situ hybridization technologies was adopted in detecting circulating tumor cells in peripheral blood,to evaluate the detection rate of CTCs in colorectal cancer patients.Clinical data of 121 CRC patients were summarized,including gender,age,tumor site,degree of tumor de-differentiation,primary lesion invasion depth(T stage),regional lymph node invasion degree(N stage),distant metastasis(M stage),TNM stage and serum CEA level at the same time.The correlation between CTCs counts and clinical pathological characteristics was analyzed.The difference of CTCs between PD group and CR+PR+SD group was compared with RECIST standard,then the relationship between CTCs and the curative effect of chemotherapy in CRC patients was obtained.All patients were followed up for survival until the end of November,2018.Statistical analysis focused on the associations between CTCs counts and clinicopathological variables.Overall survival(OS)and progression-free survival(PFS)among different prognostic factors were calculated using the Kaplan–Meier method,and the differences between the survival curves were compared by using the log-rank test.Factors of prognostic significance were investigated with the multivariate Cox regression analysis.Results(1)The detection rate of CTCs was 86% in the experimental group and 21.7% in the control group(P<0.001).The optimal critical value was 3 cells/7.5m L blood(AUC=0.935.95% CI: 0.894-0.976);The positive rate of CTCs was 58.7% in the experimental group and 0 in the control group(P <0.001).At this time,the sensitivity and specificity of CTCs detection of CRC were 61.2% and 100%,respectively.(2)In the experimental group,CTCs-positive rate was positively correlated with the depth of tumor invasion,lymphatic invasion,distant metastasis,TNM stage,and serum CEA level(P<0.05 for all).However,no significant difference was found between CTCs-positive and other clinicopathological variables(P>0.05 for all),such as gender,age,tumor location,and tumor de-differentiation.CTCs counts gradually increased with the advancement of depth of tumor invasion(P=0.002),lymphatic invasion(P=0.004),distant metastasis(P=0.007),TNM stage(P=0.001),serum CEA level(P=0.001),and decreased tumor de-differentiation(P=0.011).(3)Among the 121 CRC patients,81 patients were in the CR/PR/SD group,and 47 patients of them were CTCs positive(58%).There were 40 patients in the PD group,including 35 patients with CTCs positive(87.5%),and the difference in CTCs positive rate between the two groups was statistically significant(P=0.001).(4)The Kaplan–Meier survival curves showed that patients with CTCs-positive had a significantly unfavorable PFS(14 vs.23 months,P=0.001)and OS(18 vs.25 months,P=0.003).The multivariate Cox regression analyses revealed that the presence of CTCs during chemotherapy was an independent factor for unfavorable PFS(hazard ratio(HR): 2.682,P = 0.017,95% confidence interval(CI): 1.193-6.029)and OS(HR: 2.790,P=0.048,95% CI: 1.010-7.705)in advanced CRC patients.Conclusions(1)Immunomagnetic bead negative enrichment combined with immunofluorescence in situ impurity can eliminate the interference of epithelial markers,increase the sensitivity of CTCs detection and improve the detection rate.(2)CTCs counts was significantly correlated with tumor invasion depth,lymphatic invasion,distant metastasis,TNM stage and serum CEA level in patients with advanced CRC,which can be used as an auxiliary indicator for follow-up of clinical CRC patients.(3)CTCs counts is correlated with chemotherapy efficacy of advanced CRC,and dynamic monitoring of CTCs might be used as a auxiliary indicator for early evaluation of chemotherapy efficacy.(4)The risk of recurrence of patients with advanced CRC with CTCs positive was significantly increased,and CTCs had a certain value in the evaluation of tumor recurrence and metastasis,and CTCs counts were associated with poor prognosis,which have certain guiding significance for clinical work,but the detection rate of CTCs and the expanded sample size still need to be further confirmed.