Beta-Blockers Use and Risk of Breast Cancer in Women with Hypertension

The risk of breast cancer among hypertensive patients who use beta-blockers has attracted attention. However, the evidence is inconsistent and investigation of the dose-specific associations for subtypes of beta-blockers is limited.By incorporating Swedish national registers, breast cancer risk was estimated in women with hypertension who used nonselective beta-blockers and beta-1 selective blockers compared with propensity score-matched nonusers. The cumulative defined daily dose was used to study the dose-response association. Test of interaction between beta-blocker use and other antihypertensive medications was performed.Hypertensive patients taking beta-1 selective blockers (metoprolol, atenolol, bisoprolol) had an increased risk of breast cancer with a HR and 95% confidence interval (CI) of 2.39 (1.95-2.94), 2.31 (1.46-3.64), and 3.02 (2.09-4.36), respectively. All of the observed associations were dose-dependent (Ptrend < 0.0001). No significant association was found for the nonselective beta-blocker (propranolol) except that among users of agents acting on the renin-angiotensin system, those who used propranolol had increased breast cancer risk. Modification of agents acting on the renin-angiotensin system on breast cancer risk was also observed for atenolol.The increased risk of breast cancer associates with the use of beta-1 selective blockers in a dose-response manner.Breast cancer surveillance is recommended for hypertensive female patients using beta-1 selective blockers.