Real-world insights into young-onset gastroesophageal adenocarcinoma: an all-Ireland population-based cancer registry analysis

Background: Population-based studies report a rising incidence of young-onset (YO) oesophageal and gastric cancer. We examined clinicopathological features, treatment, and outcomes in YO (18-50 years), midlife-onset (MO, 50-70 years), and late-onset (LO, >70 years) oesophageal and gastric adenocarcinoma. Methods: Population-based data were collected from the National Cancer Registry Ireland (NCRI) and Northern Ireland Cancer Registry (NICR). Incidence trends were determined using Joinpoint regression. Kaplan-Meier curves, log-rank tests, and multivariable Cox regression were used to assess survival differences. Multivariable Cox regression was adjusted for key clinical covariates, and excluded patients with missing covariates. Results: < 0.001, multivariable Cox analysis]. Conclusion: Oesophageal adenocarcinoma incidence is rising across all age groups, while gastric adenocarcinoma incidence was stable in the YO population and declining in older adults. Despite more advanced and aggressive disease at presentation, YO patients had better overall survival.