Objective:We evaluated the prognostic factors of patients with stage IV gastric cancer.Methods:In the current retrospective study,138 patients of stage I gastric cancer treated with platinum-based chemotherapy were analyzed.Survival rate was estimated by using Kaplan-Meier method.The prognostic factors were analyzed using univariate (Log rank) and multivariate (Cox model) analysis methods.Results:Univariate analysis showed and multivariate analysis showed that poor performance status (P=0.001),weight loss (P=0.001),depth of invasion (P=0.000),presence of peritoneal metastasis (P=0.005),more than 1 metastatic site (P=0.029) and elevated total bilirubin (P=0.018) were confirmed as independent prognostic factors.According to the outcomes of the Cox model analysis,a formula of the prognostic index was developed.According to the values of PI,16 patients were categorized as the good risk group,28 patients were categorized as the moderate risk group and 8 patients were categorized as the poor risk group,respectively.The survival ratios of 6 months,12 months and 24 months of the good risk group were 75.00%,50.00%,25.00%,respectively.The survival ratios of 6 month,1-year and 2-year of the moderate risk group were 71.79%,28.57%,7.14%,respectively.While the survival ratios of 6 month,12 months and 24 months of the poor risk group were 50%,0,0,respectively.The overall survival ratios of the 3 groups were compared in pairs.Conclusion:Poor performance status,depth of invasion,elevated total bilirubin,more than 1 metastatic site,presence of peritoneal metastasis,weight loss were the independent prognostic factors.A formula of the prognostic index was developed,and it could help clinicians and patients in clinical decision-making and treatment tailoring based on the estimated prognosis. Objective: We evaluated the prognostic factors of patients with stage IV gastric cancer. Methods: In the current retrospective study, 138 patients of stage I gastric cancer treated with platinum-based chemotherapy were analyzed. Survival rate was estimated by using Kaplan-Meier method. The prognostic factors were analyzed using univariate (Log rank) and multivariate (Cox model) analysis methods. Results: Univariate analysis showed and multivariate analysis showed that poor performance status (P = 0.001), weight loss (P = 0.001), depth of invasion (P = 0.000), presence of peritoneal metastasis (P = 0.005), more than 1 metastatic site (P = 0.029) and elevated total bilirubin (P = 0.018) were confirmed as independent prognostic factors. According to the outcomes of the Cox model analysis, a formula of the prognostic index was developed. According to the values ​​of PI, 16 patients were categorized as the good risk group, 28 patients were categorized as the moderate risk group and 8 patients were categorized as the poor risk group, respectively. The survival ratios of 6 months, 12 months and 24 months of the good risk groups were 75.00%, 50.00%, 25.00%, respectively. The survival ratios of 6 month, 1-year and 2-year of the moderate risk groups were 71.79%, 28.57%, 7.14%, respectively.While the survival ratios of 6 month, 12 months and 24 months of the poor risk group were 50%, 0,0, respectively.The overall survival ratios of the 3 groups were compared in pairs. Confound: Poor performance status, depth of invasion, elevated total bilirubin, more than 1 metastatic site, presence of peritoneal metastasis, weight loss were independent prognostic factors. A formula of the prognostic index was developed, and it could help clinicians and patients in clinical decision-making and treatment tailoring based on the estimated prognosis.