Disparities in demographics, clinical features, and outcomes of early-onset colon cancer in the US.

e15700 Background: The incidence of early-onset colon cancer (EO-CC) is rising, but it remains unclear whether EO-CC represents a biologically distinct entity compared to colon cancer in patients aged > 50g. This study analyzed early-onset CC demographics, clinical features, and outcomes using the National Cancer Database (NCDB). Methods: Patients with colon adenocarcinoma (2010–2020) were identified in the NCDB and categorized as aged 18–50 or over 50. Baseline characteristics were compared using descriptive statistics. We used Kaplan-Meier and Cox proportional hazard models to analyze survival. Results: A total of 75,365 early-onset and 571,982 older CC patients were identified. EO-CC patients were more likely male (52% vs. 49%, p < 0.001), privately insured (70.2% vs. 27%, p < 0.001), and treated at academic facilities (56% vs. 48%, p < 0.001). They had more left-sided disease (51% vs. 33%, p < 0.001), advanced stages at diagnosis (Stage IV: 31.5% vs. 22.4%; p < 0.001), KRAS mutations (9% vs. 5.4%), and MSI-high cases (2.6% vs. 1.8%). Older patients had worse survival than early-onset CC patients on both univariate analysis (5-year survival: 54.2% vs 66.9%, p < 0.001) and multivariate analysis with hazard’s ratio (HR) of 1.63 (95% CI: 1.61–1.66, p < 0.001). Among EO-CC patients, African Americans had worse survival compared to Caucasians (HR: 1.21, 95% CI: 1.17–1.26, p < 0.001). Further stratification of EO-CRC by age (18–30, 31–40, and 41–50 years) revealed that patients aged 18–30 were more likely to have MSI-high status (5.1% vs 2.1%, p < 0.001), lymphovascular invasion (32% vs 27.8%, p < 0.001), and perineural invasion (23.8% vs 16.6%, p < 0.001) compared to those aged 41–50. On univariate analysis, patients aged 18-30 had worse survival compared to those aged 31-40 and 41-50 (median OS 40.5 vs 42.2 vs 43.8 months, p = 0.001). On multivariate analysis, patients aged 31-40 had better survival than those aged 18-30 (HR: 0.92, 95% CI 0.85-0.98, p = 0.02), while no significant difference was observed between patients aged 18-30 and 41-50 (HR:0.95, 95% CI 0.89 – 1.01, p = 0.2). Conclusions: Early-onset CC is diagnosed at later stages and exhibits distinct clinical features compared to CC in older patients. Patients aged 18–30 experience more aggressive disease, with worse survival due to higher perineural and lymphovascular invasion rates. These findings highlight the heterogeneity within EO-CRC and underscore the need for further research to better understand age-related differences in survival and treatment outcomes.