A remarkable new study presented at the seventh European Breast Cancer Conference (EBCC7) in Spain has reported that beta-blockers (commonly used to treat high blood pressure) might protect against metastasis in breast cancer patients. Prior studies have reported that neurotransmitters might induce cancer cell migration mediated by beta2-adrenergic receptors (β2AR). Therefore, treatment of breast cancer patients with beta-blockers might protect against the development of metastasis, resulting in improved clinical outcomes. The study included 466 breast cancer patients with operable nonmetastatic breast cancer divided into three groups: those who were being treated for hypertension by beta-blockers, those with hypertension who were being treated by other medications, and those without hypertension. Levels of one of the target receptors for beta-blockers, β2AR, was assessed as a potential biomarker of clinical outcome.

Ninety-two of the 466 patients received antihypertensive treatment and 43 of them were on beta-blockers at the time of breast cancer diagnosis. This subset of patients experienced a significant reduction in both local recurrence and distant metastasis. Furthermore, these patients had increased survival and a 71% reduced risk of breast cancer-specific mortality. However, β2AR expression failed to predict clinical outcome. The authors conclude that beta-blocker treatment appears to significantly reduce metastasis and mortality in breast cancer patients. However, measurement of one of the beta-blocker target receptors, β2AR, was not shown to be predictive of clinical outcome and other beta-blocker targets need investigating. The authors comment that additional studies are needed to validate the use of beta-blockers as a possible adjuvant therapy in breast cancer.