MRI-Derived Lymph Nodes Morphological and Topological Structure (LNs-MTS) Model for Evaluating Immune Status and Prognosis in Rectal Cancer.

Tumor-draining lymph nodes (LNs) immune status critically influences cancer progression and treatment response, yet reliable non-invasive assessment remains clinically unavailable. To address this critical gap, an MRI-derived LNs morphological and topological structure (LNs-MTS) model is developed to evaluate the immune status of LNs in rectal cancer (RC). Integrating multicenter imaging, transcriptomic, and immunohistochemical data from 1,156 stage I-II RC patients, enhanced immune activation in non-metastatic LNs sized ≥0.5 cm and located ≥5 cm from the primary tumor is discovered. Then two quantitative MRI-derived imaging features across 7,030 radiologically annotated LNs: total LNs volume (tLNV) and total LNs drainage distance (tLND) is developed, forming the basis of the LNs-MTS model risk subtypes: high-risk (HRS), moderate-risk (MRS), and low-risk (LRS). Patients in the LRS (characterized by large tLNV and distant tLND) show robust immune cell infiltration in the tumor microenvironment and excellent 5-year survival, whereas HRS (characterized by small tLNV and near tLND) show stromal dominance and poorer prognosis. Clinically, LNs-MTS offers a more precise and personalized risk assessment than current guideline-based risk stratification, potentially sparing stage II-LRS patients from unnecessary adjuvant treatment while identifying stage I-HRS individuals for more aggressive treatment, providing valuable insights for personalized treatment strategies in RC management.