Clinical Study Of Plasma Circulating Free DNA And CEA In Colorectal Cancer

Objective:To quantify plasma ccfDNA levels in colorectal cancer patients and healthy volunteers at different stages,analyze the relationship between plasma ccfDNA and related clinical features in patients with colorectal cancer,evaluate its significance for clinical diagnosis of colorectal cancer.METHODS:A total of 97 patients with newly diagnosed colorectal cancer and 36 healthy checkups who were admitted to the Third Affiliated Hospital of Soochow University from September 2016 to November 2017 were collected.The patients were subjected to TMN staging according to the colonoscopy,surgical,and imaging findings(according to the AJCC Rev 8 Cancer Staging Manual).The medical staff collected peripheral blood from the elbow veins of patients and healthy checkers with 5ml EDTA anticoagulant vacuum tubes and quantified the plasma ccfDNA by fluorescence quantitative PCR.Two independent sample t test and Mann-Whitney U test were used to analyze the relationship between the quantitative detection of plasma ccfDNA and the clinicopathological features of patients with colorectal cancer.The ROC curve was used to analyze the diagnostic value of ccfDNA quantitative detection for colorectal cancer.RESULTS:The mean plasma ccfDNA concentration(47.35±18.53)ng/ml was significantly higher in the patient group than in the healthy group(13.91±9.78)ng/ml(P<0.001).Data analysis revealed a significant difference in plasma ccfDNA levels between different degrees of colorectal cancer(P<0.001).Further analysis also showed that the ccfDNA concentration was not significantly different for other clinical features such as age,sex,lymph nodes,and staging(P>0.05).The area under the ROC curve(AUC)of 0.952(95%CI,0.917-0.987)and sensitivity(85.56%)in the diagnosis of colorectal cancer by plasma ccfDNA was higher than that of the clinically used tumor marker CEA.It is fully demonstrated that ccfDNA has a high value in the diagnosis of CRC.Conclusion:The difference between ccfDNA concentrations in CRC patients and healthy volunteers indicates that plasma ccfDNA has clinical value in clinical diagnosis of colorectal cancer and provides an effective means for clinical diagnosis of colorectal cancer.These findings suggest that ccfDNA is expected to be a new generation of noninvasive tumor markers.