Treatment-specific CT Radiomics Models To Predict Response To Neoadjuvant Therapy And Explore Individualized Treatment Selection In Gastric Cancer.

RATIONALE AND OBJECTIVES: To develop and compare general and treatment-specific radiomics models based on pretreatment computed tomography (CT) for predicting pathological response to neoadjuvant therapy (NAT) in gastric cancer (GC), and to explore a dual-score framework for individualized treatment selection. MATERIALS AND METHODS: This retrospective study included 405 patients with GC who underwent neoadjuvant chemotherapy (NAC) or neoadjuvant immunochemotherapy (NAIC) followed by radical gastrectomy, comprising 337 in the development cohort and 68 in a temporal test cohort. The development cohort was randomly divided into training (n = 235) and validation (n = 102) sets. Radiomics features were extracted from portal venous-phase CT images. Four machine learning classifiers were used to construct general and treatment-specific models. Treatment-specific models were cross-applied to generate paired NAC and NAIC response probabilities. RESULTS: In validation, the general model achieved an AUC of 0.679 (NAC, 0.732; NAIC, 0.659), whereas the NAC-specific and NAIC-specific models achieved AUCs of 0.770 and 0.753. Repeated random-split analyses more frequently favored treatment-specific models. In the temporal test cohort, the NAIC-specific model outperformed the general model (AUC, 0.707 vs 0.626), whereas the NAC-specific model showed no advantage (AUC, 0.563 vs 0.625). In the dual-score framework, patients who received model-recommended treatment showed higher pathological response rates (NAC-recommended: 46.4% vs 23.3%, p = 0.043; NAIC-recommended: 40.5% vs 19.4%, p < 0.0001). CONCLUSION: Treatment-specific radiomics models showed better discrimination than the general model for predicting pathological response to NAT in gastric cancer. The dual-score framework may provide an exploratory approach for individualized treatment selection.