Determinants of recurrence after curative gastrectomy in young-onset gastric cancer: A Latin American cohort.

e16132 Background: Young-onset gastric cancer with curative surgery have limited data on prognostic factors. We evaluated clinicopathological, nutritional and inflammatory features associated with recurrence in young patients undergoing gastrectomy for gastric adenocarcinoma. Methods: This is a retrospective observational cohort study with patients ≤45 years and gastric adenocarcinoma who underwent curative-intent gastrectomy between 2009 - 2020 at a Latin American cancer center. Collected variables included: T and N stage, overall pathological stage, Lauren classification, presence of signet ring cell component, lymphovascular invasion (LVI), and perineural invasion. Pathological variables were dichotomized as follows: T1–2 vs T3–4, N0 vs N+, and stage I–II vs stage III. Preoperative inflammatory and nutritional biomarkers (albumin, neutrophil, lymphocyte, and platelet counts) were used to calculate the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), and prognostic nutritional index (PNI). Biomarkers were summarized as medians and dichotomized using cohort-specific medians for survival analyses. The primary outcome was recurrence-free survival (RFS), estimated using the Kaplan–Meier method and analyzed using Cox proportional hazards regression. Results: 87 patients were included (median age 40 years, IQR 37–44), and 52% were female. Tumor recurrence occurred in 36 patients (41%). Patients with recurrence had a significantly higher prevalence of advanced pathological disease, including T3–4 tumors (100% vs 84%, p = 0.019), nodal involvement (94% vs 73%, p = 0.009), and stage III disease (86% vs 62%, p = 0.014). Lymphovascular invasion was also more frequent among patients with recurrence. No significant differences were observed according to age, sex, Lauren classification, or presence of signet ring cell component. Median preoperative levels of albumin, NLR, PLR, SII, and PNI did not differ significantly. The median RFS was 4.9 years (95% CI 3.0–not reached). Estimated RFS rates at 1, 3, and 5 years were 89.8%, 60.9%, and 49.8%, respectively. Node-positive patients exhibited significantly worse RFS compared with node-negative patients (log-rank p = 0.001). In univariate Cox regression analysis, nodal involvement and lymphovascular invasion were significantly associated with increased risk of recurrence. However, in multivariate analysis, pathological nodal status remained the only independent predictor of recurrence. Conclusions: In young patients undergoing curative gastrectomy for gastric cancer, recurrence is primarily driven by pathological indicators of tumor dissemination, particularly nodal involvement. Preoperative inflammatory and nutritional biomarkers were not independently associated with recurrence in this cohort.