Baseline Mortality-Adjusted Survival in Resected Rectal Cancer Patients

Abstract

BackgroundThis investigation assessed the baseline mortality-adjusted 5-year survival after open rectal cancer resection. MethodsThe 5-year survival rate was analyzed in 885 consecutive American Joint Committee on Cancer (AJCC) stage I–IV rectal cancer patients undergoing open resection between 2002 and 2011 using risk-adjusted Cox proportional hazards regression models adjusted for population-based baseline mortality. ResultsThe 5-year relative and overall survival rates were 80.9 %(95 % confidence interval (CI): 77.0–85.0 %) and 71.9 %(95 % CI, 68.4–75.5 %), respectively. The 5-year relative survival rates for stage I, II, III, and IV cancer were 97.8 % (95 % CI, 93.1–102.8 %), 90.9 %(95 % CI, 84.3–98.1 %), 72.0 % (95 % CI, 64.7–80.1 %), and 24.4 % (95 % CI: 16.0–37.0 %), respectively. After the curative resection of stage I–III rectal cancer, fewer than every other observed death was cancer-related. The 5-year relative survival rate for stage I cancer did not differ from the matched average national baseline mortality rate (P = 0.419). Higher age (hazard ratio (HR) 0.94, 95 % CI: 0.92–0.95, P < 0.001) was protective for relative survival but unfavorable for overall survival (HR 1.04, 95 % CI: 1.02–1.05, P < 0.001). Female gender was only unfavorable for relative survival (HR 1.59, 95 % CI: 1.11–2.29, P = 0.014). ConclusionThe analysis of relative survival in a large cohort of rectal cancer patients revealed that stage I rectal cancer is fully curable. The findings regarding age and gender may explain the conflicting results obtained to date from studies based on overall survival.