The Utility Of CT In The Assessment Of Response Neoadjuvant Chemotherapy In Advanced Gastric Cancer

Objective： Although the incidence of gastric cancer is decreasingworldwide,it is still a major cause of cancer-related morbidity and mortalityworldwide,the survival rates are generally very low because the patientsusually have a high stage disease at diagnosis.Recent,many studies indomestic and foreign have shown that the gastric cancer preoperativechemotherapy can make the tumor downstaging,improve the resection rate andsurvival time.Currently,the lack of a unified standards for gastric cancerpreoperative chemotherapy curative effect evaluation,and the curative effect ofpreoperative objective and accurate evaluation to choose the treatment planand prognosis of inference is very important.Now, the clinical applicationmore used TNM stages of change,or therapeutic effect evaluation standard ofRECIST,calculated before and after chemotherapy tumor longest diameterchange on curative effect evaluation.It is worth nothing that the multislicespiral CT(MSCT) for N staging accuracy is not ideal,the chemotherapy afterthe accuracy in T staging is also reduced.Gastric cancerclassification,peristalsis of the stomach,the cavity filling degree and thetumors had chemotherapy itself changes affect the sccuracy of the length todiameter measurement.A variety of post-processing technology and softwaredevelopment,multislice spiral CT in the assessment of preoperativechemotherapy efficacy for advanced gastric cancer(AGC) showed more andmore advantages.Because of tumor volume measurement is influenced bygeometric shape of object is relatively small,mainly studies in domestic andforeign are measure tumor volume change by MSCT to evaluate the efficacyof preoperative chemotherapy of advanced gastric cancert.In this study,we use MSCT enhanced scan before and after preoperativechemotherapy in advanced gastric cancer,record the change of tumor volume,density and thickness,compared with RECIST guideline,to discussefficacy evaluation of preoperative chemotherapy by MSCT scanning inadvanced gastric cancer,initially identified the best indicator for indicator forthe evaluation of the efficiency of chemotherapy in advanced gastric cancerbefore surgery.The data is processed by SPSS13.0statistics software,P<0.05think difference is statistically significant.Methods：Select clinical data of89cases of gastric cancer patients whoconfirmed by gastroscope pathology from December2010to January2013inThe Fourth Hospital of Hebei Medical University,66cases were male and23female,age range is31~78,the average age was57.51±10.96.All patientsunderwent MSCT enhanced scan,imaging evaluation for T3or T4,and nodistant metastases,previously without chemotherapy treatment,and nosignificant chemotherapy taboos.Preoperative accept2-3cycles ofchemotherapy,1week after the end of chemotherapy all patients were acceptMSCT enhanced scan evaluation again.Measured the longestdiameter,volume,density and thickness in pre-and-post-chemotherapy,calculatethe changes of all the data.Recording to the Response Evaluation Criteria insolid Tumor(RECIST1.1) to evaluate the effect of preoperative chemotherapy,divided into complete remission (CR),partly remission (PR),stable disease(SD),progression disease (PR),CR and PR classified as effective group,SD andPD classified as invalid group. Each measurement data for statistical analysis,with the Response Evaluation Criteria in solid Tumor(RECIST1.1) ofcorrelation analysis,using receiver operating characteristic curve (ROC),trying to find out the best indicators of MSCT enhanced scan in advancedgastric cancer chemotherapy curative effect evaluation,to determine theoptimal threshold and the sensitivity and specificity.Results：1Chemotherapy average age difference between effective and ineffectivegroup has no statistically significant (P=0.941).2Chemotherapy gender difference between effective and ineffectivegroup has no statistically significant(P=0.617). 3Tumor density(69.61±14.59HU) post-chemotherapy compared withpre-chemotherapy(69.61±14.59HU) sightly reduce,(P=0.000),tumor volume(71.2±52.45cm3) post-chemotherapy compared with pre-chemotherapy(78.07±50.33cm3) slightly reduce,(P=0.033),tumor thickness(13.25±3.58mm)post-chemotherapy compare with pre-chemotherapy(14.58±4.28mm) slightlyreduce,(P=0.006),all three were statistically significant.4The percentage reduction rate of the density in effective group andineffective group was18.73%±14.78%and11.34%±9.31%(P=0.024),thedifference was statistically significant;Effective group and ineffective groupvolume decrease rate were36.51%±12.24%and12.57%±9.16%(P=0.01),thedifference was statistically significant;Effective group and ineffective groupthickness reduction rate were14.58%±4.28%and7.4%±5.92%(P=0.201), thedifference of two group no statistically significant.5The percentage volume reduction rate was moderately correlated withthe Response Evaluation Criteria in solid Tumor(r=0.547,P=0.001),thepercentage density reduction rate was low correlated with the ResponseEvaluation Criteria in solid Tumor(r=0.547,P=0.001).6The area of tumor volume reduced rates pre-and-post-chemotherapyunder the curve was0.907(0.784~1.031).If the cutoff value of the volumereduction rate of the tumor was set to be11.73%,a specificity of66.7%and asensitivity of100%were achieved.Conclusions：1.Tumor volume measurement and density based on MSCT can helppredict.2.Tumor volume reduced rates show better correlation with the ResponseEvaluation Criteria in solid Tumor than density reduced rates.3.If the cutoff value of the volume reduction rate of the tumor was set tobe11.73%, a specificity of66.7%and a sensitivity of100%were achieved.