Study On The Difference Of Body Components And Distant Metastasis In Patients With Gastric Cancer Before And After Treatment Based On QCT

PART 1Study on the changes of body components in different gender patients with gastric cancer before and after treatment based on QCTObjective: To explore the changes of body components in different gender patients with gastric cancer before and after treatment.Methods: The results of abdominal CT scan were analyzed in 64 male and 53 female patients with gastric cancer before and after treatment.QCT PRO was used for body composition analysis.The content of subcutaneous fat area(SFA),visceral fat area(VFA)in the middle of L3 were measured,and Total fat area(TFA)in the middle of L3 was calculated.As well as the VFA/SFA at the central level of L3.The fat area and muscle area of posterior muscular were measured at the central level of L3,and the degree of intramuscular fat infiltration of posterior muscular infiltration(MFI)was calculated at the central level of L3.The bone mineral density(BMD)of L1 and L2 was calculated for comparison.The differences between groups conform to the normal distribution group using the paired sample t-test,and if it does not meet the match,the Wilcoxon symbol rank test is used.The difference in p<0.05 was statistically significant.Results: The fat area and posterior muscle area of the posterior muscle group at the middle level of L3 were reviewed for the first time after treatment,and the SFA,VFA,TFA and BMD at the middle level of L3 showed a downward trend compared with before treatment,and the difference was statistically significant(p<0.05).The female patients were re-examined for the first time after treatment,and the muscle fat area and posterior muscle area of the L3 middle level were re-examined for the first time,and the SFA,VFA,TFA and BMD at the middle level of L3 showed a downward trend compared with before treatment,and the difference was statistically significant(p<0.05).There was no significant difference between MFI and VFA/SFA at the middle level of L3 after treatment in male and female patients after surgery(p>0.05).In all patients,the fat area of the posterior muscle group at the middle level of L3,the muscle area of the posterior muscle group at the middle level of L3,and the SFA,VFA,TFA and BMD at the middle level of L3 were retested for the first time after treatment,all of which showed a decreasing trend compared with the preoperative level,and the difference was statistically significant(p<0.05).There were no significant differences between MFI and L3 middle level VFA/SFA in the first review after treatment(p>0.05).After comparison,it was found that whether it was male patients,female patients,or all patients: the degree of VFA decrease at the middle level of L3 was the most obvious than that of other statistically significant observations.Conclusions :1、The muscle fat area and muscle area of posterior vertebral muscles at the middle level of L3,SFA,VFA,TFA and BMD at the middle level of L3 were decreased compared with those before treatment in patients of different genders.2、In patients with gastric cancer,the decrease of VFA at L3 level in the first review after treatment was the most obvious compared with other statistically significant observation indicators.PART 2Preoperative abdominal fat content in predicting distant metastasis after radical gastrectomy for gastric cancer based on QCTObjective: To explore the influencing factors of preoperative subcutaneous fat area(SFA)at L3 level,visceral fat area(VFA)at L3 level,VFA/SFA at L3 level and muscle fat infiltration(MFI)of L3 vertebral posterior muscle group on distant metastasis after radical gastrectomy for gastric cancer.Methods: The pre-operative abdominal CT images of 47 patients with gastric cancer metastasis after radical gastrectomy and 89 patients without metastasis for 5 years or more after radical gastrectomy in Yijishan Hospital of Wan Nan Medical College from 2015 to 2022 were analyzed.Abdominal fat analysis was performed using QCT PRO software,and SFA at L3-level,VFA at L3-level,VFA at L3-level/SFA at L3-level,and posterior spinal muscle group MFI at L3-level were obtained.The measurement data conformed to the normal distribution and the independent sample T test was used to compare the two groups.The quantitative parameter data of the nonnormal distribution were used by the Mann-Whitney U test;Two tests were used for comparison of counting data groups;Univariate and multivariate binary logistic regression analysis was performed on the influencing factors of predicting metastasis in gastric cancer patients.The ROC curve was used to determine the optimal cut-off value of the independent influencing factor of gastric cancer metastasis.Results: VFA at L3 level and VFA/SFA at L3 level in distant metastasis group were significantly higher than those in non-metastasis group(P < 0.05).There was no significant difference in MFI and SFA between distant metastasis group and non-metastasis group(P > 0.05).Univariate and multivariate logistic regression analysis showed that increased VFA/SFA at L3 level would increase the risk of distant metastasis after radical resection of gastric cancer patients,and the difference was statistically significant(P<0.05).The difference was still statistically significant(P<0.05)after multivariable adjustment.The increase of VFA at L3 level also increased the risk of distant metastasis after radical resection in gastric cancer patients,but the difference was not statistically significant after multivariate regression analysis(P > 0.05).The AUC value of VFA/SFA at L3 level calculated by ROC curve was 0.710(0.618-0.803),and its critical value was calculated as1.71.Conclusions :1、VFA at L3 level and VFA/SFA at L3 level are risk factors for distant metastasis in patients with gastric cancer after radical resection.2、High VFA/SFA at L3 level is a risk factor for distant metastasis after radical gastrectomy;It is also an independent factor of distant metastasis after radical gastrectomy.