Association Between Use of β-Blockers and Prostate Cancer–Specific Survival: A Cohort Study of 3561 Prostate Cancer Patients with High-Risk or Metastatic Disease

Abstract

BackgroundWe recently reported reduced prostate cancer (PCa)–specific mortality for β-blocker users among patients receiving androgen-deprivation therapy in a health survey cohort including 655 PCa patients. Information on clinical characteristics was limited. ObjectiveTo assess the association between β-blockers and PCa-specific mortality in a cohort of 3561 prostate cancer patients with high-risk or metastatic disease, and to address potential confounding from the use of statins or acetylsalicylic acid (ASA). Design, setting, and participantsClinical information from all men reported to the Cancer Registry of Norway with a PCa diagnosis between 2004 and 2009 (n=24 571) was coupled with information on filled prescriptions between 2004 and 2011 from the Norwegian Prescription Database. Exclusion criteria were low- or intermediate-risk disease; planned radiotherapy or radical prostatectomy; initiation of β-blocker, ASA, or statin use after diagnosis where applicable; missing information on baseline Gleason score, prostate-specific antigen level, T stage or performance status; and missing follow-up. Outcome measurements and statistical analysisCox proportional hazards modelling and competing risk regression modelling were used to analyse the effects of β-blocker use on all-cause and PCa-specific mortality, respectively. Differences between β-blocker users and nonusers regarding baseline clinical characteristics were assessed by the Wilcoxon-Mann-Whitney U test, Pearson chi-square test, and Student t test. Results and limitationsMedian follow-up was 39 mo. β-Blocker use was associated with reduced PCa mortality (adjusted subhazard ratio: 0.79; 95% confidence interval [CI], 0.68–0.91; p value: 0.001). The observed reduction in PCa mortality was independent of the use of statins or ASA. We observed no association with all-cause mortality (adjusted hazard ratio: 0.92; 95% CI, 0.83–1.02). The main limitations of the study were the observational study design and short follow-up. Conclusionsβ-Blocker use was associated with reduced PCa-specific mortality in patients with high-risk or metastatic disease at the time of diagnosis. Our findings need validation from further observational studies.