Early- and late-onset gastric cancer: comparison of demographic, clinical and histopathological characteristics and their association with five-year mortality

To compare the clinical and pathological characteristics of early-onset gastric cancer (EOGC, < 50 years) versus late-onset gastric cancer (LOGC, ≥ 50 years) and evaluate independent determinants of overall mortality in a multicenter Latin American cohort. A retrospective cohort study was conducted across five oncology centers in Colombia (2019–2023). Patients aged ≥ 18 years with histologically confirmed primary gastric cancer staged under the AJCC 8th edition were included; other gastric histologies and prior or synchronous malignancies were excluded. Overall survival was assessed using Kaplan–Meier curves, the log-rank test, and multivariable Cox proportional hazards models with multiple imputation and complete case analysis. Of 1413 included patients, 252 (17.8%) had EOGC and 1,161 (82.2%) had LOGC. EOGC patients presented with a higher proportion of diffuse subtype (53.6% vs. 28.3%) and stage IV presentation (61.5% vs. 47.9%). Across a median follow-up of 3.96 years, 1074 deaths (76.0%) were documented. Unadjusted overall survival did not differ significantly between cohorts (log-rank p = 0.91). However, upon multivariable adjustment with multiple imputation, EOGC was independently associated with lower mortality compared with LOGC (adjusted HR 0.81, 95% CI 0.68–0.95, p = 0.011). Advanced AJCC stage, diffuse histology, and alcohol consumption were independent determinants of increased mortality across the cohort. EOGC presented with more diffuse-type and stage IV disease than LOGC, with no difference in unadjusted survival. After multivariable adjustment, EOGC was independently associated with lower mortality. This supports a clinically distinct profile for EOGC and reinforces the need for earlier diagnostic suspicion in this age group.