Abstract
PURPOSE: To establish a pragmatic prognostic nomogram for predicting the survival of elderly patients undergoing gastrectomy for gastric adenocarcinoma. PATIENTS AND METHODS: Data of elderly patients undergoing gastrectomy for gastric adenocarcinoma between 2004 and 2015 were obtained from the Surveillance, Epidemiology, and End Results database. Prognostic factors were identified by the Kaplan-Meier method and the Cox proportional hazards model. Based on these factors, we developed a nomogram to predict the overall survival (OS) and gastric cancer-specific survival (GCSS). Concordance index (C-index) and calibration curve are employed to assess the predictive accuracy of the model. Decision curve analysis (DCA) and receiver operating characteristic curve (ROC) analysis are applied to further appraise the clinical utility of the model. RESULTS: A total of 8401 cases were incorporated into this research. After univariate and multivariate analyses, nine prognostic factors of OS were identified, including age (P < 0.001), race (P < 0.001), marital status (P < 0.001), tumor site (P < 0.001), tumor size (P = 0.024), differentiation (P < 0.001), T stage (P < 0.001), N stage (P < 0.001), and M stage (P < 0.001); ten prognostic factors of GCSS were identified, including age (P < 0.001), race (P < 0.001), tumor site (P < 0.001), tumor size (P = 0.002), differentiation (P < 0.001), T stage (P < 0.001), N stage (P < 0.001), M stage (P < 0.001), radiotherapy (P < 0.001) and chemotherapy (P < 0.001). The C-index of the constructed nomogram for OS was 0.708 (95% CI: 0.701-0.715) while for GCSS was 0.745 (95% CI: 0.737-0.753). The calibration curves of the nomogram predictions and actual observations displayed good agreement for the 3- and 5-year OS and GCSS probabilities. The results of DCA and the area under the curve calculated by ROC analysis showed that the developed model was superior than TNM stage. CONCLUSION: The nomogram we established could accurately predict the prognosis of individual elderly patients who underwent gastrectomy for gastric adenocarcinoma.