Establishment of a novel survival assessment and prediction model for advanced gastric cancer patients receiving immunotherapy

Currently, there are only a few risk assessment tools that provide predictions of survival duration for patients with gastric cancer (GC) receiving immunotherapy. The purpose of the present study was to develop and validate a nomogram that uses statistical data to predict survival and make risk assessments for patients with advanced staged GC. A total of 1,013 patients consisting of a development cohort (n=501) and validation cohort (n=512) collected during the time interval between January 2018 and June 2022 were included in the present study. The analysis consisted of the discrimination index, calibration plots and decision curve of the nomogram model. A total of 167 (33.33%) patients from the development cohort, and 158 (30.85%) from the validation cohort died during the observation period. The median overall survival (OS) of female patients was higher at 980 days (95% CI, 613-NA) compared with that of male patients, which was 748 days (95% CI, 597-NA; P=0.24). The median survival of patients with domestic immunotherapy was 789 (95% CI, 597-NA) days, which was lower compared with the imported immunotherapy group who had a median OS of 980 days (95% CI, 582-NA; P=0.22). A total of four independent predictors, age (HR=1.012; P=0.0245), histological grade (HR=1.395; P=0.016), immunotherapy cycles (HR=0.932; P=0.028) and line of first immunotherapy (HR=1.693; P=0.0003), were identified. The C-index was 0.64 and 0.67 for the development and validation cohorts, respectively. Patients who received more cycles of immunotherapy as the first-line treatment with highly differentiated tumor led to increase in the survival time of the patients. Thus, this nomogram could be used to determine the benefit of immunotherapies on patients at various stages of treatment of GC.