A LODDS and PNI-based personalized prognostic model for patients with gastric cancer receiving neoadjuvant chemotherapy.

BACKGROUND: This study aimed to develop and validate a risk stratification model incorporating the log odds of positive lymph nodes (LODDS) and the prognostic nutritional index (PNI) to predict outcomes in patients with locally advanced gastric cancer (LAGC) undergoing neoadjuvant chemotherapy (NAC). METHODS: A retrospective cohort of patients with NAC-LAGC who underwent radical gastrectomy between January 2016 and January 2025 was enrolled. The cohort was randomly split into a training set and a validation set at a 7:3 ratio. Independent risk factors were identified through univariable and multivariable Cox regression analyses in the training set. An individualized nomogram for progression-free survival (PFS) and a risk stratification model were subsequently developed. Model performance was evaluated using the area under the receiver operating characteristic (ROC) curve (AUC), calibration curves, and decision curve analysis (DCA), and was further validated in the validation set. RESULTS: A total of 450 patients were included. In the training set, 255 (79.2%) were male, and 67 (20.8%) were female; 96 (29.8%) were under 60 years, and 226 (70.2%) were 60 years or older. Multivariable analysis identified LODDS, PNI, age, tumor regression grade (TRG), and ypT stage as independent risk factors for PFS. The nomogram based on LODDS outperformed the ypN stage-based nomogram (AUCs at 3, 4, and 5 years: 0.916 vs. 0.888, 0.917 vs. 0.867, and 0.935 vs. 0.876, respectively; all P < 0.05 by Delong test). To enhance risk stratification, a prognostic model (LTTAP) was developed, demonstrating robust predictive performance with all AUCs exceeding 0.850 and a concordance index (C-index) of 0.826. DCA further confirmed that LTTAP provided a meaningful clinical net benefit for NAC-LAGC patients. CONCLUSION: The LTTAP model integrating LODDS and PNI offers strong prognostic value for patients with NAC-LAGC.