The Impact of Age on Colorectal Cancer Incidence, Treatment, and Outcomes in an Equal-Access Health Care System

BACKGROUND: Inferior outcomes in younger patients with colorectal cancer may be associated with multiple factors, including tumor biology, delayed diagnosis, disparities such as access to care, and/or treatment differences. OBJECTIVE: This study aims to examine age-based colorectal cancer outcomes in an equal-access health care system. DESIGN: This study is a retrospective large multi-institutional database analysis. PATIENTS: Patients with colorectal cancer included in the Department of Defense Automated Central Tumor Registry (January 1993 to December 2008) were stratified by age <40, 40 to 49, 50 to 79, and 80 years to determine the effect of age on incidence, treatment, and outcomes. MAIN OUTCOME MEASURES: The primary outcomes measured were the stage at presentation, adjuvant therapy use, 3- and 5-year disease-free survival, and overall survival. RESULTS: Some 7948 patients were identified; most (77%) patients were in the 50- to 79-year age group. Overall, 25% presented with stage III disease. Compared with patients aged 50 to 79 and 80 years, patients aged <40 and 40 to 49 years presented more frequently with advanced disease (stage III (35% and 35% vs 28% and 26%) and stage IV (24% and 21% vs 18% and 15%); all p < 0.001). Adjuvant chemotherapy use in stage III patients was 62%; those patients 80 and 50 to 79 years had decreased use (p < 0.001). Overall recurrence was 8.1% at 3 years and 9.7% at 5 years, with the highest rates in patients <40 years (11.8%; p = 0.007). Overall survival was worse in patients 80 years, whereas the remaining cohorts were similar. For stage III disease, patients 40 to 49 years had the highest survival among all cohorts (p < 0.001). LIMITATIONS: This study was limited by the lack of specific comorbid information and the limitations inherent to large database reviews. CONCLUSIONS: In an equal-access system, young age at presentation (<50 years) was associated with advanced stage and higher recurrence of colorectal cancer, but similar survival in comparison with older patients. Although increased adjuvant therapy use in younger patients may partially account for stage-specific increases in survival, the relative decreased chemotherapy use overall requires further evaluation.