A foundation model-enhanced CT radiomics signature for the noninvasive assessment of tertiary lymphoid structures and prediction of therapy benefit in gastric cancer

Development, validation, and clinical utility of the FMRS for TLS prediction and survival stratification. (A) Overview of the study workflow, including patient selection, data collection, and cohort allocation. (B) Schematic illustration of the CT-based framework for predicting TLS status with the foundation model-enhanced radiomics signature (FMRS). (C, D) Receiver operating characteristic (ROC) curves demonstrating FMRS performance for TLS classification in the training cohort (C) and validation cohort (D). (E, F) Confusion matrices showing agreement between FMRS-predicted TLS status and histopathological assessment in the training cohort (E) and validation cohort (F); correctly classified cases are shown along the diagonal, and misclassifications are shown off the diagonal. (G–J) Kaplan–Meier survival analyses, stratified by FMRS status: overall survival (OS) in the training cohort (G) and validation cohort (H), and disease-free survival (DFS) in the training cohort (I) and validation cohort (J). (K–M) Kaplan–Meier curves for OS, comparing FMRS-high and FMRS-low groups in the internal neoadjuvant therapy cohorts: all patients (K), neoadjuvant chemotherapy subgroup (L), and neoadjuvant immunotherapy subgroup (M). (N) Kaplan–Meier analysis of OS according to FMRS status in the external neoadjuvant chemotherapy validation cohort. AUC, area under the curve; FMRS, foundation model-enhanced CT radiomics signature; H&E, hematoxylin–eosin staining; HR, hazard ratio; IHC, immunohistochemistry; TLS, tertiary lymphoid structure; WSI, whole slide scanning.