Application Of Circulating Tumor Cell Detection In Patients With Colorectal Cancer

Objective: Colorectal cancer(CRC)is a common gastrointestinal tumor,which ranks third in morbidity and second in mortality rate worldwide.Even if some patients have received radical surgery,they still cannot get rid of recurrence and metastasis.Recurrence and metastasis are the main reasons that affect the prognosis and death of colorectal cancer patients.Epithelial mesenchymal transition(EMT)refers to the process by which epithelial cells are transformed into cells with mesenchymal phenotype through a specific procedure,and it is an important progress involved in tumor metastasis.Circulating tumor cells(CTC)refers to tumor cells that enter the peripheral blood circulation from the primary tumor or metastasis lesions of the tumor.CTC with EMT characteristics have recently been identified in the bloodstream of patients with metastatic disease.So,the detection of CTC could be helpful to determine the prognosis and clinical treatment of colorectal cancer.At present,there are many studies on CTC,but some results of these studies are contradictory and divergent.Although many approaches have been developed for the isolation and characterization of CTC,however,none of these methods can be considered the gold standard for CTC detection.Some results lacks of large sample research as well.In this study,the negative separation method and immunofluorescence in situ hybridization technology were used to isolate and identify CTC.To demonstrate the reliability of CTC as a diagnostic indicator for colorectal cancer clinical utility,we detected the number of CTC before and after operation in colorectal cancer patients,and analyze the correlation between CTC and tumor differentiation,lymph node metastasis,TNM staging and other pathological outcome indicators.Methods: 23 patients with colorectal cancer came from the Second Department of General Surgery,Ningbo Zhenhai People’s Hospital at the time in Mar 2017 to Oct 2019 were enrolled.Peripheral venous blood samples(4ml)were taken before operation and 1 week after operation to detect CTC.All cases have completed pathological diagnosis results after surgery.Analyze the difference of CTC before and after operation,and discuss the relationship between CTC and clinicopathological characteristics.Results:1 The expression of CTC in the peripheral blood of patients: 23 colorectal cancer cases were enrolled,15 males and 8 females,with an average age of 64.30 ± 9.24 years.Overall 17(73.9%)of23 patients had CTC in the peripheral blood before surgery,and 14 patients(60.9%)after operation.2 The results of CTC detection were statistically different at group of preoperative and postoperative: 2.261 ± 2.359(preoperative group)and 1.304 ± 1.636(postoperative group),the results showed statistical differences(t = 2.630,P = 0.015).3 The results of CTC detection before surgery are related to the depth of tumor invasion:according to the different invasion depths of colorectal cancer tissue,they were divided into three groups,7 cases in the T1+T2 group(0.429 ± 0.535),11 cases in the T3 group(2.364 ± 2.157),5cases in the T4 group(4.600 ± 2.408).The results showed that there were statistical differences between the three groups.4 The results of CTC detection before surgery are related to whether the tumor has local lymph node metastasis: 10 cases in the group of lymph node metastasis(3.500 ± 2.593),13 cases in the group of none lymph node metastasis(1.308 ± 1.702),and there is statistical significance between the two groups(p = 0.023).5 The results of CTC detection before surgery are related to whether the tumor has distant metastasis: 17 cases in the none distant metastasis group(1.529 ± 1.625),6 cases in the distant metastasis group(4.333 ± 3.011),there is statistical significance between the two groups(P=0.009).6 The results of CTC detection before surgery were not related to the degree of tumor differentiation: 5 cases in the poorly differentiated group(3.200 ± 2.588),10 cases in the moderately differentiated group(2.000 ± 2.494),8 case in the highly differentiated group(2.000 ±2.359),there was no statistical difference between the three groups.Conclusions:1 The expression of CTC in circulating blood of patients with colorectal cancer will decrease at the time of one week after surgery.2 The expression of CTC is correlated with the depth of invasion,lymph node metastasis and distant metastasis in colorectal cancer patients.3 The expression of CTC has no correlation with the degree of tumor differentiation in patients with colorectal cancer.