摘要Objective:To explore the independent factors associated with the overall survival(OS)after D2/R0 resection and adjuvant chemoradiotherapy(CRT)for stage Ⅲ gastric cancer(GC)and gastroesophageal junction(GEJ)cancer,and establish and validate a nomogram model to predict the OS in this patient population.Methods:A total of 569 stage Ⅲ GC or GEJ cancer patients who underwent D2/R0 resection and adjuvant CRT at our center from January 2013 to May 2018 were retrospectively enrolled in this study.The patients were randomly divided into training and validation cohorts in a 3:1 ratio.In the training cohort,univariate and multivariate analysis were conducted to identify clinical factors associated with OS,and a nomogram model was established on the basis of the independent factors.The concordance index(C-index)and the calibration curve were used to validate the prediction power of the nomogram.Results:Overall,427 and 142 patients were enrolled in the training and validation cohorts,respectively.In the univariate and multivariate analyses,age,Lauren's classification,TNM stage,and administration of adjuvant CRT were independent factors for OS to construct the nomogram.The C-index values were 0.654 and 0.613 in the training and validation cohorts,respectively.The calibration curves were identical to the actual OS.Risk strati-fication based on the nomogram model showed good risk stratification for OS in both groups.Conclusion:Our study included adjuvant CRT as a predictive factor and established a nomogram model for pre-dicting the OS in patients with stage Ⅲ GC or GEJ after D2/R0 resection and adjuvant therapy.This nomogram could facilitate more individualized prediction of OS in clinical practice.