Study On The Relationship Between Tumor Cells In Peripheral Blood Circulation And The Number Of Immune Cell Subsets Before And After Operation In Patients With Colorectal Cancer

Aims:The number of circulating tumor cells in the peripheral blood of patients with colorectal cancer can help to determine the prognosis of patients.However,its number may be affected by many factors.This study aims to explore the correlation between perioperative CTC detection and tumor clinicopathological characteristics in CRC patients and probe the impact of immune status on perioperative CTC detection by monitoring the dynamic changes and correlation of peripheral blood CTC and immune cell subsets during perioperative period,so as to provide a reference for the value of CTC detection in the perioperative period,the time of CTC detection after operation,and whether multiple detections are needed.Methods:In this study,38 patients with colorectal cancer who were admitted to the Second Affiliated Hospital of Nanchang University from October 1^st2020 to December 31^st2020 were prospectively included.The clinicopathological data of the patients were reviewed,and the peripheral blood of the patients’median cubital vein was extracted1 day before surgery,3 days after surgery,and 7 days after surgery.Negative enrichment combined with immuno-fluorescence in situ hybridization（im-FISH）was used to detect and count CTC in peripheral blood of the patients.At the same time,peripheral blood immune cell subsets were detected by flow cytometry.In addition,10 patients with benign colorectal disease diagnosed by pathology as adenoma were collected,and their peripheral blood was collected for CTC detection as control.The differences of CTC detection in patients with different diseases and at different time points and the correlation between CTC detection and clinicopathological features of tumors were analyzed.Receiver operating characteristic（ROC）curve and area under ROC curve（AUC）were used to evaluate the potential value of CTC as a biomarker in the diagnosis of CRC patients.Pearson correlation coefficient was used to study the correlation between CTC and immune cell subsets,and to explore the influence of immune status on CTC detection during the perioperative period.Results:Compared with patients with colorectal benign diseases（adenoma）,the positive detection rate and the number of CTC in CRC patients were higher than those in the control group（P=0.001,P<0.0001）,which proved that negative enrichment combined with im-FISH technology could be used for the detection of peripheral blood CTC in colorectal cancer.The area under the ROC curve showed that the ability to diagnose colorectal cancer was better when CTC was combined with tumor markers CEA and CA199（AUC=0.929,95%CI:0.843-1.000,P<0.001）.In addition,the positive detection rate of CTC was related to the degree of tumor differentiation,depth of invasion and TNM staging（P=0.010,P=0.028,P=0.016）.More importantly,by dynamically monitoring the changes of peripheral blood CTC and immune cell subsets in patients with colorectal cancer,it was found that peripheral blood lymphocytes（CD4+T,B cells and NK cells）showed a downward trend after 3 days（P=0.002,P=0.005,P=0.007）,suggesting that the body’s immune function was suppressed in the early postoperative period.The CTC counts showed an upward trend 3 days after surgery compared with preoperatively（P=0.0004）,and the numbers of CD4+T,CD8+T and NK cells were negatively correlated with CTC（r=-0.806,P=0.005;r=-0.642,P=0.04;r=-0.667,P=0.035）.The CTC counts dropped after 7 days（P<0.0001）.It suggested that the CTC counts in the perioperative period changed dynamically and had a certain correlation with the immune status of the body.Conclusion:The preoperative CTC counts and clinicopathological characteristics presented a good correlation.The counts of CTC in the perioperative period changed dynamically,which had a certain correlation with the immune status of the body.Sampling at a single time point after surgery for CTC detection may not be sufficient for reliable clinical relevance assessment due to variation in immune status.Dynamic monitoring of CTC levels during the perioperative period may provide more comprehensive information for evaluating prognosis.