CT And DEXA Study Of The Relationship Between Body Fat And Postoperative Prognosis In Gastric Cancer Patients

Objective:To investigate the correlation between CT and DEXA quantitative of abdominal fat and postoperative prognosis in gastric cancer patients,find the effect of nutrition status on prognosis of patients,compare the correlation between CT and DEXA,and provide basis for nutritional status assessment and clinical treatment.Materials and methods:1.This study included 65 patients with histo-pathologically proved as gastric adenocarcinoma who underwent gastrectomy at First Affiliated Hospital of Guangxi Medical University,identified between March 2016 and March 2018,including 46 men,19 women,mean age 57(range,22~86)years.Gender,age,height,weight,albumin,prealbumin,tumor pathological type,differentiation degree,preoperative TNM-staging,vascular cancer embolus,type of surgical procedure,volume of bleeding,and tumor diameter were collected from hospital information system.Including open gastrectomy in 47 cases and laparoscopic gastrectomy in 18 cases.Based on the NRS 2002(nutritional risk screening2002)score patients were divided into non-nutritional risk group(total score less than 3)and nutritional risk group(total score 3 or more).All patients were followed up mainly by means of telephones and re-diagnosis,The follow-up duration was 2 years,mean 13.5(range,3~24)months.At the end of the follow-up 48 patients survived and 17 died.2.All patients were underwent whole abdomen CT and DEXA examination before operation.After examination,the images were transfered to AW4.6 and Ziostation post-processing working station to measure abdominal fat area including visceral fat area(VFA),subcutaneous fat area(SFA),total fat area(TFA)and L3 skeletal muscle indes.3.All the data were analyzed by SPSS 22.0 and MedCalc v15.8 statistical software.The compare means between two measurement data groups were analyzed by t-test,while the enumeration data were analyzed byχ~2 test or Fisher’s exact test.The correlation between two measurement data groups were analyzed by Pearson test linear correlation anlalysis.The assessed value of body fat to nutritional status of patients was estimated through Logistic regression analysis.The ROC curve was created through the nutritional status of patients to identify diagnostic thresholds of body fat area.The relationship between body fat and postoperative prognosis of gastric cancer patients was analyzed by Cox multiple regression analysis.Kaplan-Meier analysis was used for create the survival curve,the compare between two groups were analyzed by Log-rank test.P<0.05 statistically indicated a significant difference.Results:1.There were statistically significant difference between non-nutritional risk group and nutritional risk group,including TNM-staging,Z-TFA,Z-VFA,Z-SFA,C-TFA,C-VFA,C-SFA,E-VAT,E-Android,E-Total,Z-L3 skeletal muscle indes,C-L3 skeletal muscle indes and E-L3 skeletal muscle indes(P<0.05).2.Through correlation analysis this study found a negative correlation between nutritional risk and the various of body fat area,L3 skeletal muscle indes(P<0.05).3.Logistic regression analysis showed that Z-SFA,C-SFA could be used to assess nutritional risk of gastric cancer patients(P<0.05).4.There were statistically significant difference between survived group and died group,including Z-TFA,Z-VFA,Z-SFA,C-TFA,C-VFA,C-SFA,E-Android,E-Total,C-L3 skeletal muscle indes,E-L3 skeletal muscle indes and TNM-staging(P<0.05).Cox multiple regression analysis showed that Z-SFA,C-SFA,TNM-staging were independent factors in postoperative prognosis of gastric cancer patients(P<0.05).5.According to ROC analysis,the areas under curve of C-SFA were 0.756,when the C-SFA value as 87.27 cm~2,the Youden index was maximal,the sensitivity was 75.00%and the specificity was 77.42%.The areas under curve of Z-SFA were 0.750,when the Z-SFA value as 85.34 cm~2,the Youden index was maximal,the sensitivity was 75.00%and the specificity was 74.19%.6.Survival analysis(K-M)curve showed that the postoperative survival rate of high C-SFA value group(SFA>87.27cm~2)was higher than low C-SFA value group(SFA≤87.27cm~2).Similarly,the postoperative survival rate of high Z-SFA value group(SFA>85.34cm~2)was higher than low Z-SFA value group(SFA≤85.34cm~2).The survival rate with the passage of time gradually decreased.7.There was a significant positive relationship between AW4.6 and Ziostation post-processing working station to measure the various of body fat area and L3 skeletal muscle indes(r=0.960~0.996,P<0.01).The above correlation coefficient of was higher than the correlation coefficient between DEXA and AW4.6 or ZIOSTATION post-processing working station measurement methods(r=0.697~0.841,P<0.01).8.The result of effects of different surgical methods on body fat area and some related indicators in gastric cancer patients show:1 month after gastrectomy body fat area were less than the value of preoperative in two groups(open gastrectomy group and laparoscopic group),with a significant difference(P<0.05),the survival rate of laparoscopic group is higher(P<0.05).Conclusion:1.CT can located and quantitify the abdominal fat quickly and accurately,and dynamic assessment the body fat of patients.SFA associate the nutritional status and postoperative prognosis of gastric cancer patients,can be used as supplement and application of nutrition monitoring index to predict nutritional status impact on postoperative prognosis.2.AW4.6 and Ziostation post-processing working station fat measurement methods can substitute each other.However,the correlation between these two methods and DEXA measurement method was relatively lower,and DEXA cannot measure subcutaneous fat area,so DEXA cannot substitute above two methods.3.AW4.6 post-processing working station fat measurement as gold standard,the diagnostic thresholds of SFA may be 87.27cm~2,less than 87.27cm~2patients may suffer nutritional risk and have a poor prognosis.4.After gastrectomy body fat area were less than the value of preoperative,the prognosis of laparoscopic group much better.