Clinical Study Based On CT Extracellular Volume Fraction To Predict The Efficacy Of Neoadjuvant Chemotherapy For Gastric Cancer

Objective: To predict the efficacy of neoadjuvant chemotherapy(NAC)in patients with locally advanced gastric cancer(LAGC)by extracellular volume fraction(ECV)calculated during equilibrium phase of multi-slice helical CT(MDCT).Materials and methods: Patients with advanced gastric cancer who underwent radical resection in the Affiliated Hospital of Inner Mongolia Medical University from April 2017 to May 2022 were collected,received a complete NAC treatment regimen,and underwent MDCT-enhanced scanning before NAC.Postoperative pathology was divided into grade 0-1 responsive group and grade 2-3 non-response group according to the 2021 National Comprehensive Cancer Network(NCCN)guidelines for gastric cancer.By comparing clinicopathological variables,CT variables and ECV between the two groups,the CT variables included the non-contrast CT value of the lesion region of interest(ROI),the enhanced tertiary CT value,the absolute enhanced CT difference between each stage(△S1,△S2,△S3),the non-contrast abdominal aorta scan,the equilibrium CT value and the equilibrium absolute enhanced CT difference(△S4).The accuracy of each CT variable was analyzed by SPSS statistical software,and the within-group correlation coefficient(ICC)was calculated.Continuous numeric variables were tested using either the independent sample t-test or the Mann-Whitney U test.Categorical data were compared using either the Chi-square test or the Fisher test.Spearman or Pearson correlation analysis was used to assess the correlation of each variable with TRG.The statistically different variables screened by univariate analysis were performed for multivariate analysis,and independent predictors of NAC efficacy were screened out by binary logistic regression,and joint predictors were constructed.The diagnostic efficacy of independent and combined predictors was evaluated by ROC curves.The difference between AUCs was compared using the Delong test.Results: A total of 49 patients with an average age of 61.35 years were enrolled in this study.Among them,there were 24 cases in the reaction group and 25 cases in the non-reaction group.1.The difference between tumor T stage(P=0.009)and ECV(P=0.000)was statistically significant,and there was no significant difference in gender,age,tumor location,histological grade and lymph node status between the two groups(P≥0.05).2.Among the CT variables,there were statistical differences between the equilibrium CT values(p=0.012)and △S3(P=0.004).3.Tumor T stage(r=-0.367,P=0.011)was negatively correlated with pathological TRG,equilibrium CT(r=0.355,p=0.012)was positively correlated with pathological TRG by low degree,and ECV(r=0.505,P=0.000)and △S3(r=0.403,P=0.004)were moderately positively correlated with pathological TRG.4.The results of multivariate analysis showed that ECV and T stage were independent predictors of NAC efficacy in patients with LAC(p=0.043 and p=0.047,respectively).5.The ROC curve comparison results showed that the AUC of ECV was 0.773(95% CI: 0.641～0.906),with 39.83% as the cut-off value,sensitivity of 66.7%,and specificity of 84.0%;The AUC of tumor T stage was 0.691(95% CI: 0.543～0.839),bounded by 3,with a sensitivity of 62.5% and a specificity of 88.0%.The AUC of the combined predictor L was 0.837(95% CI: 0.723～0.950),with a threshold of 0.56,a sensitivity of 70.8%,and a specificity of 88.0%.6.There was a significant difference between the T stage and the AUC of the combined predictor L(P=0.044),and there was no significant difference between the T stage and the AUC of ECV(P=0.394)and the combined predictor L(P=0.129).Conclusion: ECV,T stage,equilibrium CT value and △S3 are the influencing factors for predicting the efficacy of NAC in LACC patients,among which ECV and T stage are their independent predictors,which can be used as biological indicators for non-invasive evaluation of NAC efficacy in LADC patients,and ECV,T stage and combined predictor L have certain accuracy in predicting the efficacy of NAC in patients with LACC,which can provide a reference for accurate prediction of NAC efficacy in patients with LAC in the future.