Based On CT Imaging To Identify Lauren’s Classification And The Effect Of Proximal Margin On The Prognosis Of Esophagogastric Junction Adenocarcinoma

Chapter 1 The role of radiomics in improving the accuracy of Lauren’s classification of gastric adenocarcinomasObjective:The aim of the study was to develop and validate a radiomics nomogram to improve the accuracy of distinguishing the Lauren’s classification of gastric adenocarcinomas(GA).Methods:The prediction model was developed in a cohort that consisted of 430 patients(training cohort vs.validation cohort:284 vs.146)with clinicopathologically confirmed GA from January 2014 to December 2018.All patients received computed tomography(CT)and radiomic features were extracted.LASSO regression were used for data dimensional reduction,feature selection and radiomics signature building.We incorporated the radiomics signature and independent clinicopathologic risk factors to develop the radiomics nomogram.The performance of the nomogram was assessed with respect to calibration,discrimination,and clinical usefulness.Subject operating characteristic(ROC)curves were used to evaluate the efficacy of the imaging histology labels and the joint model for predicting Lauren’s staging in the training and validation sets,respectively,and the area under the curve(AUC)was calculated.Calibration curves were used to assess the of the preoperative prediction of Lauren typing by the joint prediction model to the true state of postoperative pathology,and decision curve analysis(DCA)was used to calculate the threshold probabilty of net benefit of the combined model.Results:The combined model consists of 3 key imaging labels and 3 clinical risk factors:endoscopic biopsy,age and clinical T-stage(cT stage)together.The AUC of the combined radiomic nomogram was 0.905(95%CI:0.863-0.947),with specificity of 0.859(95%CI:0.731-0.936)and sensitivity of 0.872(95%CI:0.650-0.917)in training cohort,while in validate cohort was 0.868(95%CI:0.801-0.935),with specificity of 0.860(95%CI:0.605-0.953),sensitivity of 0.816(95%CI:0.524-0.893).Decision curve analysis vertified that the radiomics nomogram was clinically useful.Conclusion:The above-described radiomics nomogram can improve the accuracy of Lauren’s classification in patients with GA preoperatively which may assist surgeons to make better therapeutic decision-making and patient counseling as a clinical tool.Chapter 2 Effect of proximal margin on the prognosis of esophagogastric junction adenocarcinomaObjective:The optimal length of the proximal margin for esophagogastric junction(EGJ)adenocarcinoma is still under debate,and the impact of survival and recurrence remains unclear.The aim of the present study was to investigate the influence of the optimal length of the proximal margin on EGJ adenocarcinoma.Methods:From January 2011 to December 2015,131 patients who diagnosed EGJ adenocarcinoma with T2-3 were included and retrospectively analyzed.All patients underwent radical R0 resection.The proximal margin was measured promptly after resection,and the frozen-section pathological examination was negative for the margin.Results:There were 3 cases of Siewert type I EGJ adenocarcinoma(2.9%),75 cases of Siewert type II EGJ adenocarcinoma(57.9%),and 53 cases(40.1%)of Siewert type Ⅲ.The median number of lymph nodes examined was 19(range:1-41),and the median number of positive lymph nodes was 2(range:0-18).Sixty-three patients underwent total gastrectomy(48.1%),and 68 underwent proximal gastrectomy(51.9%).The median follow-up time was 57.3 months:(range 1.9-174.1);34 patients(26%)relapsed and 74(56.5%)died.The 5-year overall survival rate of T2 patients was 68.2%,and that of T3 patients was 38.5%(P=0.013).For patients with a proximal margin<1 cm,the median survival time was 50.7 months,whereas it was for 60.9 months for patients with proximal margin>1 cm(log-rank:0.048).Our data analysis found that a proximal margin length of 1cm with negative was a prognostic variable for EGJ adenocarcinoma patients.Conclusion:There are a number of factors associated with recurrence and overall survival for patients who have EGJ adenocarcinoma with T2-3,and a negative proximal margin>1 cm may indicate better prognosis.Besides,The length of the proximal margin does not affect recurrence while ensuring invisibility of the proximal margin,without influences on recurrence.