Women's Heart Advisor April 2012 Issue

Beta-Blockers May Help With Breast Cancer Treatment

May help prevent heart failure and death from metastatic disease.

In the July 2011 Women’s Heart Advisor, we discussed research confirming that radiation therapy for breast cancer prior to 1984, as well as the presence of benign breast calcifications, both increase the risk of coronary artery disease.

Now there’s more evidence supporting a breast-heart connection, but this time, the news is good. Two recent studies suggest that beta-blockers may reduce the cardiovascular side effects of chemotherapy and, possibly, prevent tumors from spreading.

Beta-blockers are commonly prescribed to heart patients. They lower blood pressure and help the heart pump more easily by blocking adrenalin, thereby preventing the arteries from constricting. Common beta-blockers include metroprolol (Lopressor, Toprol XL), atenolol (Tenormin), carvedilol (Coreg), nadolol (Corgard) and propranolol (Inderal).

Lowering Risk of Heart Failure
A preliminary study conducted at Cleveland Clinic indicates that beta-blockers may protect the heart during treatment with trastuzumab (Herceptin). This targeted monoclonal antibody therapy used in human epidermal receptor 2-positive (HER2+) breast cancer increases the cancer-killing power of other chemotherapy drugs for some patients and is used alone in others when other drugs have failed. But it is not without risks of its own, which include the development of heart failure.

In the Cleveland Clinic study, which was presented at the American Heart Association annual meeting in November 2011, beta-blockers reduced the likelihood of developing heart failure after one year of trastuzumab therapy by 65 percent. Of the 197 participants, none who took a beta-blocker developed heart failure, while 11 percent of those who were not taking a beta-blocker did. After adjusting for traditional cardiovascular risk factors that can lead to heart failure, including radiation therapy and cancer treatment with anthracyclines, beta-blockers lowered the risk of developing heart failure on trastuzumab by 83 percent.

In contrast, nearly nine percent of patients taking trastuzumab were taking ACE inhibitors, but this medication did not stop the heart from failing.

Preventing Cancer from Spreading
Ninety percent of deaths from breast cancer occur when the cancer spreads (metastasizes) to other parts of the body. Finding a way to stop metastasis is key to improving survival. A recent study suggests beta-blockers may help.

In November 2010, researchers in the UK reported that beta-blocker therapy reduced the risk of metastatsis, recurrence and death in a study of 466 patients with operable breast cancer. The patients were divided into three groups: taking beta-blockers for hypertension; taking a different drug for hypertension; and taking none of these drugs. After more than 10 years of followup, the women who took beta-blockers had a 57 percent lower risk of metastatic disease and a 71 percent lower chance of dying from breast cancer.

As a result of the this study, Cancer Research UK has funded a larger study. The outcome will be used to verify whether clinical trials to determine which beta-blocker works best are warranted.