The study reviewed here found that women diagnosed with breast cancer who also were taking a beta-blocker high blood pressure medicine were much less likely to develop metastatic breast cancer (cancer that has spread to parts of the body away from the breast) or to die from breast cancer compared to women who weren't taking a beta-blocker. These results were presented at the 2010 European Breast Cancer Conference.
Beta-blockers treat high blood pressure by blocking beta receptors. Blocking beta receptors blocks the effect of the hormone epinephrine, also known as adrenaline, on the body. Beta receptors are in many tissues, including blood vessels, the heart, and the lungs. Some common beta-blockers used to treat high blood pressure are:
Other research has shown that a build-up of beta receptors in breast cancer cells is associated with the growth and spread of breast cancer. Beta-blockers can reduce the effect of this increase in beta receptors.
So doctors wondered if beta-blockers might improve breast cancer prognosis.
In this study, researchers looked at the medical records of 466 women diagnosed with early-stage breast cancer. Some of the women were taking blood pressure medicine for at least 1 year before being diagnosed with breast cancer:
All the women had similar breast cancer treatment plans, including chemotherapy after surgery to reduce the risk of the cancer coming back (recurrence).
The women were followed for about 10 years.
Compared to women who weren't treated for high blood pressure or women who took a high blood pressure medicine that wasn't a beta-blocker, women who took a beta blocker were:
While these results seem promising, it's important to remember that the women in this study who were taking a beta-blocker had been diagnosed with high blood pressure and were taking the beta-blocker before being diagnosed with breast cancer. They weren't given a beta-blocker as part of the study. So while the results suggest a strong association between beta-blockers and better breast cancer prognosis, they don't prove that beta-blockers are a good breast cancer treatment. More research is needed to see if beta-blockers actually improve outcomes for some women.
Stay tuned to Breastcancer.org Research News for the latest results on better ways to prevent, diagnose, and treat breast cancer.
BARCELONA (MedPage Today) -- Breast cancer patients on concomitant beta-blocker therapy had significantly better outcomes compared with other patients, including a reduced risk of metastasis and improved disease-specific survival, data from an observational study showed.
Patients taking beta blockers had a 57% reduction in the risk of distant metastasis and a 71% reduction in the risk of breast cancer-specific death, as compared with patients on other antihypertensive agents or no antihypertensive therapy, Des Powe, PhD, reported here at the European Breast Cancer Conference.
However, studies of adrenergic receptor expression showed no associations with clinical outcome.
Though preliminary, the results support previous laboratory work showing that upregulation of beta-adrenergic receptors is associated with increased breast cancer cell proliferation and migration, effects that were inhibited by beta blockers.
"Because our studies are based on previous laboratory studies, we believe our results are sufficiently convincing for urgent clinical trials to now be performed," said Powe, of Nottingham University Hospital in England.
Interest in beta blockers' therapeutic potential in cancer comes from studies linking chronic stress to cancer development and progression. Stress increases production of the adrenergic hormones epinephrine and norepinephrine, which have multiple physiologic effects, said Powe.
The effects of beta-1 and -2 on cell proliferation and migration are analogous to cancer metastasis, he added.
Following the evidence from laboratory studies, Powe and colleagues examined the effects of beta-blocker therapy on outcomes in breast cancer. They reviewed medical records of 466 patients with primary operable breast cancer treated with adjuvant chemotherapy.
The study population included 43 hypertensive patients treated with beta blockers and 49 hypertensive patients treated with other blood pressure medications. All patients on antihypertensives had been on their blood pressure medication for at least a year prior to breast cancer diagnosis.
The beta-blocker group did not differ significantly from the patients on other blood pressure medications and the nonhypertensive patients with respect to baseline demographic and clinical variables.
All patients received the same adjuvant combination chemotherapy, and follow-up averaged 10 years.
Comparing the beta-blocker group with the other patients, Powe and colleagues found a significant reduction in the hazard ratio for distant metastasis (HR 0.43, P=0.031) and breast cancer-specific death (HR 0.288, P=0.007).
Local recurrence also was reduced significantly (P=0.003).
"The fact that all the patients received similar adjuvant therapy suggests the significant benefits seen in beta-blocker treated patients cannot be explained by adjuvant therapy alone," said Powe.
In support of the clinical results, the investigators examined beta-adrenergic receptors' association with clinocopathologic features of tumor specimens from 689 breast cancer patients.
Beta-1 receptor expression showed no correlation with any of the features.
Beta-2 expression was significantly associated with estrogen receptor-positive tumors (P<0.001) and with several markers of favorable prognosis. Beta-2 expression did not predict the odds of distant metastasis, breast cancer-specific survival, disease-free interval, or recurrence.
"Beta-2 adrenergic receptor expression is not an independent predictor of clinical outcome," said Powe.
The findings add to an existing evidence base suggesting that adrenergic-receptor antagonists have anticancer activity, he added. Treatment with alpha-1 antagonists has been associated with a reduced risk of prostate cancer (J Urol 2007; 178: 2176-80). A study of patients with cardiovascular disease showed a significant reduction in total cancer incidence among patients treated with beta blockers versus those on other antihypertensive medications (Rev Epidemiol Sante Publique 2004; 52: 53-65).
Powe had no disclosures.
Primary source: European Breast Cancer Conference Source reference: Powe DG, et al "Beta-blocker treatment is associated with a reduction in tumor metastasis and an improvement in specific survival in patients with breast cancer" EBCC 2010; Abstract 445.
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