Effects of beta-blocker therapy on mortality after elective colon cancer surgery: a Swedish nationwide cohort study

OBJECTIVE: Colon cancer surgery remains associated with substantial postoperative morbidity and mortality despite advances in surgical techniques and care. The trauma of surgery triggers adrenergic hyperactivation which drives adverse stress responses. We hypothesised that outcome benefits are gained by reducing the effects of hyperadrenergic activity with beta-blocker therapy in patients undergoing colon cancer surgery. This study aims to test this hypothesis. DESIGN: Retrospective cohort study. SETTING AND PARTICIPANTS: This is a nationwide study which includes all adult patients undergoing elective colon cancer surgery in Sweden over 10 years. Patient data were collected from the Swedish Colorectal Cancer Registry. The national drugs registry was used to obtain information about beta-blocker use. Patients were subdivided into exposed and unexposed groups. The association between beta-blockade, short-term and long-term mortality was evaluated using Poisson regression, Kaplan-Meier curves and Cox regression. PRIMARY AND SECONDARY OUTCOMES: Primary outcome of interest was 1-year all-cause mortality. Secondary outcomes included 90-day all-cause and 5-year cancer-specific mortality. RESULTS: The study included 22 337 patients of whom 36.1% were prescribed preoperative beta-blockers. Survival was higher in patients on beta-blockers up to 1 year after surgery despite this group being significantly older and of higher comorbidity. Regression analysis demonstrated significant reductions in 90-day deaths (IRR 0.29, 95% CI 0.24 to 0.35, p<0.001) and a 43% risk reduction in 1-year all-cause mortality (adjusted HR 0.57, 95% CI 0.52 to 0.63, p<0.001) in beta-blocked patients. In addition, cancer-specific mortality up to 5 years after surgery was reduced in beta-blocked patients (adjusted HR 0.80, 95% CI 0.73 to 0.88, p<0.001). CONCLUSION: Preoperative beta-blockade is associated with significant reductions in postoperative short-term and long-term mortality following elective colon cancer surgery. Its potential prophylactic effect warrants further interventional studies to determine whether beta-blockade can be used as a way of improving outcomes for this patient group.