Clinical Study On The Diagnostic Value Of Plasma SEPT9 Methylation Test For Early Colorectal Cancer

[Objective](1)Kappa test was used to analyze the performance of plasma SEPT9 gene methylation(mSEPT9)in single-indicator diagnosis of CRC patients.(2)Chi-square test was used to analyze the relationship between the positive rate of plasma mSEPT9 detection and the clinical characteristics of CRC patients.(3)The positive rates of mSEPT9 in the adenoma group,the early cancer group,the advanced cancer group and the normal control group were calculated,and the chi-square test was used to analyze whether the differences were statistically significant.(4)Consistency test was used to analyze the diagnostic ability of mSEPT9 and serum CEA in the diagnosis of CRC and the efficacy of the combined diagnosis.[Methodologies]Collect patients from the Department of Digestive Medicine,Gastroenterology and Oncology at the First Affiliated Hospital of Kunming Medical University from December 2017 to December 2018,develop inclusion and exclusion criteria,the sample size was estimated to include 72 CRC patients.In this study,126 patients in the CRC group and 146 patients in the non-CRC group were included,and a total of 272 patients were further divided into the adenoma group,the early cancer group,the progressive cancer group and the normal control group.To investigate the relationship between the positive expression of mSEPT9 in plasma and the clinical characteristics of CRC patients and to compare the positive rate of mSEPT9 in each group and the diagnostic efficacy of mSEPT9 and serum CEA in CRC patients.[Results]1 The performance of plasma mSEPT9 single index in the diagnosis of CRC patients.The sensitivity and specificity of the single-indicator diagnosis of CRC in plasma mSEPT9 were 57.14%(72/126),86.99%(127/146),the positive predictive value was 79.12%and the negative predictive value was 70.17%,which were consistent with the diagnosis of gold standard(colonoscopy).P<0.001,indicating that Kappa value was statistically significant.2 The relationship between the positive rate of plasma mSEPT9 and the clinical characteristics of CRC patients.There was no statistically significant difference in the positive rate of plasma mSEPT9 detection between tumor sites and lesion sizes of different ages and genders(?2=0.170,3.122,0.071,2.098,P>0.05).The positive rate of mSEPT9 was related to tumor stage,presence of lymph node metastasis and distant metastasis,and the differences were statistically significant(?2=13.092,18.750,P<0.05),and the positive rate of early cancer was significantly lower than that of progressive cancer(33.33%VS 88.89%).3 Comparison of positive rates of mSEPT9 in each group.In this study,the cases were divided into 82 cases in the normal control group,64 cases in the adenoma group,72 cases in the early cancer group and 54 cases in the progressive cancer group,with positive rates of mSEPT9 testing(10.98%,15.63%,33.33%,88.89%).When comparing the positive rates of mSEPT9 in the four groups,the difference was statistically significant at the level ?=0.05(?2=102.615,P<0.001),suggesting that the positive rates of mSEPT9 in the four groups were not all the same.Further compared between two groups,adenoma group compared with normal control group,there was no statistically significant difference(?2=0.686,P>0.05).Compared with the normal control group,the difference between the early cancer group and the advanced cancer group was statistically significant(?2=11.382,81.183,P<0.05).Although the positive rate of the early cancer group was statistically significant compared with the normal control group,the clinical significance was not significant,because the detection rate of early cancer was only 33.33%.4 Comparison of mSEPT9,serum CEA and their combined detection in early and advanced cancer.The positive rate of all CRC patients detected by mSEPT9 was higher than that of serum CEA(57.14%VS 33.33%),and the sensitivity of the combined detection of CRC increased to 66.67%(84/126).The consistency test analysis showed that the degree of compliance with the gold standard could be improved by combined diagnosis(Kappa value of mSEPT9=0.450,Kappa value of CEA=0.225,Kappa value of combined diagnosis=0.514).In early cancer,the positive rate of mSEPT9 and CEA was 33.33%and 16.67%respectively,and the positive rate of combined diagnosis could be increased to 41.67%.In advanced cancer,the positive rate of mSEPT9 and CEA was 88.89%and 55.56%respectively,and the positive rate of combined diagnosis could reach 100%.Combined diagnosis can further improve the sensitivity in both early and advanced cancer,which has important clinical significance in early cancer screening.[Conclusions]1.The sensitivity and specificity of single indicator detection of plasma mSEPT9 for the diagnosis of CRC were 57.14%and 86.99%respectively,indicating that the diagnosis of CRC was generally consistent with the gold standard.2.The positive rate of plasma mSEPT9 was not related to the patient's age,gender,tumor site and lesion size,but related to tumor stage,presence of lymph node metastasis and distant metastasis,and the positive rate of early cancer was significantly lower than that of advanced cancer.MSEPT9 has high sensitivity in progressive cancer,which may be used as an index for evaluation of the efficacy of colorectal cancer and postoperative follow-up monitoring,and still needs clinical research verification of multicenter and large sample size.3.The diagnostic value of plasma mSEPT9 alone may be limited when it is used for adenoma and early cancer detection.4.In both early and advanced cancer,the positive rate of mSEPT9 was higher than serum CEA,and the sensitivity of both combined diagnosis could be further improved,which has important clinical significance in early cancer screening.