ARTICLE ABSTRACT
Pre-operative radiotherapy for early-stage rectal cancer has risks and benefits that may impact treatment choice in young patients. We reviewed radiotherapy use and outcomes for rectal cancer by age.
Patients with early-stage rectal cancer in the Canadian province of British Columbia from 2002-2016 were identified (n=6232). Baseline characteristics, treatment response, overall survival (OS), disease-free survival (DFS), disease-specific survival (DSS), and locoregional recurrence rate (LRR) were compared between patients <50 (early-onset) (n=532) and ≥50 years old (average-onset) (n=5700).
Early-onset patients were more likely to receive pre-operative chemoradiotherapy than short-course radiotherapy (OR: 2.20, 95% CI: 1.67-2.89, P<0.0001), but also had higher nodal (P=0.00096) and overall clinical staging (P=0.033). Cancer downstaging and pCR rates were similar in those receiving neoadjuvant chemoradiotherapy by age. Early-onset and average-onset patients had similar DSS (P=0.91) and DFS (P=0.27) in multivariate analysis unless non-colorectal deaths, which were higher in older patients, were censored in the DFS model (HR: 1.30, 95% CI: 1.01-1.68, P=0.042). LRR also did not differ between age groups (P=0.88). Outcomes did not differ based on radiotherapy type.
Young patients with rectal cancer are more likely to present with higher staging and receive long-course chemoradiotherapy. DSS did not differ by age group, however young patients had worse DFS when we censored competing risks of death in older patients.
