Stage‐specific associations between beta blocker use and prognosis after colorectal cancer

Abstract

Recent observational studies have suggested that the use of beta blockers might be associated with better prognosis after cancer. Because evidence is limited for colorectal cancer (CRC), the association of beta blocker use and prognosis was investigated in a large population-based cohort of patients with CRC. Between 2003 and 2007, information on beta blocker use at diagnosis and potential confounders was collected by personal interviews for 1975 patients with CRC. Vital status, cause of death, and recurrence status were assessed during a median follow-up time of 5.0 years. The associations of beta blocker use and overall, CRC-specific, and recurrence-free survival were estimated by Cox proportional hazard regression. In addition, beta blocker subgroup, site, and stage-specific analyses were performed. After adjustment for covariates including sociodemographic, cancer-related, and lifestyle factors and comorbidity and medications, no significant association between beta blocker use at diagnosis and prognosis was observed for all stages combined. However, in stage-specific analyses, beta blocker use was associated with longer overall survival (hazard ratio = 0.50; 95% confidence interval = 0.33-0.78) and CRC-specific survival (hazard ratio = 0.47; 95% confidence interval = 0.30-0.75) in stage IV patients. For these patients, median overall survival was 18 months longer and CRC-specific survival was 17 months longer for beta blocker users than for nonusers (38 versus 20 months and 37 versus 20 months, respectively). These results suggest that beta blocker use might be associated with longer survival in patients with stage IV CRC.