Multi-slice Spiral CT 3D Reconstruction In Neoadjuvant Chemotherapy In Advanced Gastric Cancer Application Value Of Efficacy Evaluation

Objective: to measure the volume of gastric cancer lesions by multi-slice spiral CT three-dimensional reconstruction technology,analyze the effect of volume change and thickness change of gastric cancer before and after chemotherapy in the evaluation of neoadjuvant chemotherapy efficacy,and predict the accuracy of postoperative pathological evaluation of chemotherapy efficacy.Objective to explore the application value of multi-slice spiral CT three-dimensional reconstruction technology in the evaluation of neoadjuvant chemotherapy for advanced gastric cancer.Methods: the clinical data of 67 patients with advanced gastric cancer who met the inclusion criteria in the Department of gastrointestinal surgery,Affiliated Hospital of Qinghai University from November 2017 to November 2019 were retrospectively analyzed.All patients were diagnosed by endoscopy and pathology,and had received neoadjuvant chemotherapy and later radical gastrectomy.Methods: 67 patients with advanced gastric cancer underwent MSCT examination of stomach or upper abdomen before neoadjuvant chemotherapy and before operation.According to the CT image,the maximum thickness of tumor was measured.In addition,three-dimensional reconstruction was performed on the image,and the tumor volume was measured.According to Becker’s standard,the patients were divided into two groups:pathological effective group(residual tumor < 50%)and pathological ineffective group(residual tumor > 50%).In order to understand the correlation between the observation indexes and postoperative pathological TRG,Spearman correlation test was used to analyze the relationship between the changes of each index and postoperative pathological TRG grading.ROC curve was drawn to analyze the change rate of tumor thickness and volume,and to predict the accuracy of postoperative pathological evaluation of chemotherapy efficacy.Results: in the evaluation of chemotherapy efficacy,the change rate of tumor thickness and volume can be used to evaluate the efficacy of chemotherapy to a certain extent(P < 0.05).To further test,correlation analysis showed that the volume change rate of tumor was negatively correlated with postoperative pathological TRG(r =-0.546,P < 0.001);There was also a negative correlation between the change rate of lesion thickness measured by multi-slice spiral CT before and after chemotherapy and postoperative pathological TRG(r =-0.283,P = 0.02),that is,the larger the tumor volume and the reduction rate of tumor thickness,the smaller the TRG grade.According to the ROC curve,the area under curve(AUC)of gastric cancer volume reduction rate was 0.916,and the 95% confidence interval(CI)was(0.838,0.993);The AUC was 0.756,95% CI was(0.635,0.876).The best cut-off value of tumor volume reduction rate was 49.02%,with sensitivity of 86.2% and specificity of 94.7%;The best cut-off value was 20.80%,the sensitivity was 72.4%,and the specificity was76.3%.Therefore,compared with the tumor thickness change rate,measuring the tumor volume and calculating the volume change rate are more effective in evaluating the efficacy of neoadjuvant chemotherapy.Conclusion: MSCT 3D reconstruction can accurately measure the volume of tumor before and after chemotherapy.It is better to evaluate the curative effect of neoadjuvant chemotherapy by calculating the change rate of tumor volume before and after chemotherapy by measuring the tumor volume with CT than by measuring the maximum diameter of tumor with CT.Stomach is a hollow organ,gastrointestinal tumor is an irregular sphere,the maximum thickness of the tumor measured alone can not effectively represent the tumor regression.Using MSCT three-dimensional reconstruction technology to measure the tumor volume,the tumor volume change rate can more effectively evaluate the chemotherapy efficacy of patients,and its three-dimensional visualization structure can better observe the changes of cancer focus.Therefore,multi-slice spiral CT three-dimensional reconstruction technology is worth promoting to clinical evaluation of neoadjuvant chemotherapy.