Use of beta-blockers and risk of contralateral breast cancer
Menée au Danemark auprès d'une cohorte de 52 723 patientes atteintes d'un cancer du sein et à l'aide de données de registres, cette étude analyse l'effet d'une utilisation de bêta-bloquants sur le risque de cancer du sein controlatéral (1 444 cas)
Beta-blockers have shown anti-neoplastic effects in laboratory studies but epidemiologic evidence in relation to contralateral breast cancer (CBC) is sparse. We investigated post-diagnosis beta-blocker use and risk of CBC in a cohort of 52 723 women with breast cancer by using nationwide Danish health registers and the Danish Breast Cancer Group database. We defined post-diagnosis beta-blocker use as a time-varying covariate starting one year after a second prescription was redeemed. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for CBC associated with beta-blocker use compared with non-use. We identified 1444 women with CBC of whom 209 women were beta-blocker users. We found an overall HR of 1.08 (95% CI: 0.93-1.27) for beta-blocker use and risk of CBC with no substantial variation according to cumulative amount, intensity or selectivity of beta-blocker use. Hence, our cohort study of women with breast cancer did not sustain a protective effect of beta-blocker use on risk of CBC, irrespective of beta-blocker type.