National Trends in Rectal Cancer Among Younger Patients: A National Cancer Database Analysis

Introduction: In recent years, the incidence of new rectal cancer diagnoses among younger patients (< 50 years) has been increasing at alarming rates. Paradoxically, previous studies show that younger patients present with more advanced-stage disease; however, they have better survival rates than older individuals. In this study, we aim to examine the clinical and pathologic trends in younger patients with rectal cancer in a contemporary cohort. Methods: A retrospective cohort study of the National Cancer Database (NCDB) was conducted to examine characteristics of invasive rectal cancer diagnoses between younger (< 50 years old) and older (≥ 50 years old) individuals in a dataset from 2004 to 2021. Joinpoint regression analysis (version 5.3.0.0, U.S. National Cancer Institute, Bethesda, MD, USA) was used to examine trends in rectal cancer over time. Chi-square analyses were utilized to determine differences in proportions of patients with earlier (Stage I/II) and later (Stage III/IV) clinical stage or grade disease between patients in the two age groups. Overall survival (all-cause mortality) was compared between groups using Kaplan-Meier survival analysis. P-values < 0.05 were considered statistically significant. Results: A total of 171,543 rectal adenocarcinoma patients from NCDB were analyzed. Joinpoint analysis revealed a rise in rectal cancer rates for both older (annual percent change (APC) 4.2% from 2011 to 2021) and younger groups (5.4% from 2004 to 2021), with a more rapid increase in the younger group. Younger patients were more likely to present with advanced stage (III and IV) disease (p < 0.001) and higher-grade tumors (p < 0.001). Kaplan-Meier survival analysis showed worse median survival for younger patients at advanced (III and IV) stages of disease (-0.129 years, p = 0.016); however, there was no difference at earlier stages (p = 0.900). When stratified by tumor grade, those with higher-grade (Grade 3/4) tumors had significantly better survival than those with lower-grade (Grade 1/2) tumors (median difference: -1.071 years, p < 0.001). Conclusion: There is a rising incidence of rectal cancer in young patients, who often present with advanced disease and demonstrate worse outcomes than older patients when advanced, likely due to delayed diagnosis and treatment. The high prevalence of late-stage diagnoses underscores the need for improved awareness and targeted screening strategies to promote earlier detection. Addressing these disparities is essential to optimizing screening, care, and outcomes for these patients.