Evaluation of Demographics and Management of Rectal Cancer by Age Group: A Retrospective Propensity Matched Cohort Analysis of the National Cancer Database.

Background Data suggests there are demographic and biological differences in colon cancer between young and typical-onset patients. However, it is unclear if these differences persist in rectal cancer patients, exclusive of colon cancer. This is a retrospective review of a large national database to evaluate age-based differences in demographics, tumor features, and treatment among patients with rectal adenocarcinoma. Methods The National Cancer Database from 2004-2014 was queried for rectal adenocarcinoma. Patients were grouped by age at diagnosis: early-onset, defined as <40 years, mid-onset 40-49, and late-onset ≥50. Propensity matching controlled for demographic variation among cohorts. Pairwise Chi-square with Bonferroni correction was used for analysis. Results Thirty thousand nine hundred seventy-eight patients were included: 1,249 (4%) early-onset, 4,156 (13%) middle-onset, and 25,573 (83%) late-onset. Significant differences existed between all three cohorts in nearly all demographic and pathologic metrics. Control for demographic variation revealed early-onset and middle-onset cohorts differed only with respect to the stage at presentation, while early-onset and late-onset cohorts differed more significantly on the basis of stage, histology, and oncologic management. Conclusion The demographic differences observed demonstrate that patients under 50 should not be considered one cohort. Propensity matching led to a decrease in tumor trait differences among cohorts, suggesting that demographics other than age drive variation in tumor biology. Young patients received more aggressive management, implying the presence of an age bias. Age-based screening is likely insufficient and may exclude the rising proportion of young patients at risk for disease, while age-based management may lead to under- or overtreatment of patients at either end of the age spectrum.