Abstract: Objective To explore the factors affecting the survival of patients with advanced gastric cancer and establish a reliable predictive model of the patients' survival outcomes. Methods We retrospectively collected the clinical data from patients with advanced gastric cancer treated in our department between January, 2015 and December, 2019. Univariate survival analysis was carried out using Kaplan-Meier method followed by multivariate Cox regression analysis to identify the factors associated with the survival outcomes of the patients. The R package was used to generate the survival rates, and a nomogram was established based on the results of multivariate analysis. The calibration curves and C-index were calculated to determine the predictive and discriminatory power of the model. The performance of the nomogram model for predicting the survival outcomes of the patients was evaluated using receiver- operating characteristic (ROC) curve analysis and decision curve analysis (DCA). Results Univariate analysis showed that the number of metastatic sites, the number of treatment lines received, disease control rate (DCR) and progression-free survival (PFS) time following first-line treatment, and surgical treatment in first-line treatment were significantly correlated with the survival time of the patients (P<0.05). Multivariate Cox regression analysis showed that surgical treatment, number of treatment lines, PFS time following first-line treatment and peritoneal metastasis, as independent prognostic factors, were significantly correlated with the patients' survival (P<0.05). The C-index of the nomogram was 0.785 (95%CI: 0.744-0.826) for overall survival of the patients. The calibration curves showed that the actual survival rate of the patients was consistent with the predicted survival rate. The time-dependent AUC and DCA demonstrated that the nomogram had a good performance for predicting the survival outcomes of patients with advanced gastric cancer. Conclusion Peritoneal metastasis is associated with s shorter overall survival time of patients with advanced gastric cancer, while a PFS time following first-line treatment of more than 7.0 months and third-line and posterior-line treatments are related with a longer survival time. Systematic treatment including elective surgery can improve the survival outcomes of the patients. The nomogram we established provides a reliable prognostic model for evaluating the prognosis of patients with advanced gastric cancer.

Key words: advanced gastric cancer; over survival; prognostic factor; nomogram