Abstract
OBJECTIVE: This study aimed to identify prognostic factors incorporating preoperative IBI and MAR levels and to construct a corresponding nomogram for patients undergoing radical gastrectomy for gastric cancer. METHODS: We retrospectively analyzed 300 gastric cancer patients who underwent radical gastrectomy (June 2018-July 2021). Optimal cut-off values for preoperative IBI and MAR in predicting overall survival (OS) were determined by ROC analysis. Patients were stratified accordingly, and group differences were compared. OS was analyzed using Kaplan-Meier and log-rank tests. Independent clinicopathological prognostic factors were identified by Cox regression and used to build a nomogram predicting 1-, 3-, and 5-year survival. The model was internally validated via Bootstrap resampling and evaluated using the C-index, time-dependent ROC curves, and calibration plots. RESULTS: The optimal cut-off values for IBI and MAR were 9.045 and 10.151, respectively. High IBI or MAR was associated with aggressive tumor features (all P < 0.05). Multivariate analysis identified adjuvant therapy, N stage, CA19-9, IBI, and MAR as independent prognostic factors. The resulting nomogram showed good discrimination, with C-indices of 0.809 (training) and 0.802 (validation). The AUCs for 1-, 3-, and 5-year OS all exceeded 0.83, and calibration was accurate. The nomogram successfully stratified patients into low- and high-risk groups with significantly different survival (Log-rank P < 0.001). CONCLUSION: Preoperative IBI and MAR are robust prognostic indicators in gastric cancer. The developed nomogram provides a practical visual tool for individualized postoperative risk assessment and management.