Association of lymph node ratio with perioperative outcomes and survival in patients with early-onset gastric cancer: a multicenter retrospective cohort study.

Early-onset gastric cancer (EOGC) represents a distinct subgroup of gastric cancer with unique clinicopathological characteristics and prognostic challenges. This multicenter retrospective cohort study aimed to evaluate the association of lymph node ratio (LNR) with perioperative outcomes and long-term survival in patients with EOGC aged <50 years. A total of 544 patients who underwent radical gastrectomy were included from six tertiary hospitals. Patients were classified into low- and high-LNR groups according to the cohort median LNR (4.5%). Intraoperative indicators, postoperative complications, short-term recovery outcomes, overall survival (OS), and disease-free survival (DFS) were compared between groups. Propensity score matching and multivariable regression analyses were performed to reduce baseline imbalance and potential confounding. During a median follow-up of 15.0 months, no significant differences were observed between low- and high-LNR groups regarding operative time, intraoperative blood loss, postoperative complications, or short-term postoperative recovery indicators. However, multivariable Cox regression analysis demonstrated that high LNR was independently associated with worse OS (HR=3.279, 95% CI 1.529-7.030, p=0.002) and DFS (HR=3.266, 95% CI 1.523-7.003, p=0.002). Kaplan-Meier analyses consistently showed poorer survival outcomes in patients with high LNR. These findings indicate that LNR is associated with long-term oncological outcomes but not with perioperative recovery in patients with EOGC. LNR may serve as a complementary prognostic marker for postoperative risk stratification; however, prospective studies with standardized thresholds and longer follow-up are required for further validation.