Clinical Research Directory

MMR Status Modulates the Predictive Value of Lymphatic Invasion for Lymph Node Metastasis in Gastrointestinal Cancers

Lymph node metastasis (LNM) is a key factor influencing treatment decisions and prognosis in patients with gastric cancer. Lymphatic invasion (LI) is an important pathological predictor of LNM and a core component of the eCURA risk scoring system after endoscopic submucosal dissection (ESD) for early gastric cancer. However, whether LI has the same predictive value for LNM across different mismatch repair (MMR) statuses remains unclear. Compared with proficient mismatch repair (pMMR) gastric cancer, deficient mismatch repair (dMMR) gastric cancer has distinct molecular pathological features and an immune-enriched tumor microenvironment. In early gastric cancer, if LI is associated with a lower LNM risk in dMMR tumors than in pMMR tumors, existing LI-based eCURA risk assessment may overestimate LNM risk in patients with dMMR early gastric cancer and consequently affect decisions regarding additional surgery after ESD. Therefore, this study aims to systematically evaluate the association between MMR status, LI, and LNM using multi-center cohorts of patients with GC who underwent upfront gastrectomy or additional gastrectomy following ESD, and to explore the potential clinical value of incorporating MMR status into eCURA-based risk stratification for early GC. Furthermore, an independent colorectal cancer surgical cohort will be included to investigate whether these associations are consistent across different gastrointestinal malignancies.