Common blood pressure medications tied to breast cancer recurrence
Two classes of common blood pressure medications are linked to breast cancer recurrence. Findings from a preliminary review suggest ACE inhibitors and beta blockers have opposite effects for women with a personal history of breast cancer. ACE inhibitors may increase the chances of breast cancer returning, while beta-blockers seem to have the opposite effect and offer some protection against recurrence of the disease.
Host of factors could influence breast cancer recurrence
Writing in the journal, Breast Cancer Research and Treatment, the authors, from UCLA's Jonsson Comprehensive Cancer Center say, "There is increasing interest in the relationship between host lifestyle factors and the outcomes of cancer treatment. Behavioral factors, comorbid conditions, and non-cancer-related pharmaceutical exposures may affect breast cancer (BC) outcomes."
To find the link between the blood pressure treatment medications and cancer recurrence, the researchers looked at data from a cancer registry that included 1,779 women with early-stage breast cancer. The women were part of the Life After Cancer Epidemiology (LACE) study.
The risk of breast cancer recurrence was lower for the 14 percent of women taking beta-blockers. For women taking ACE inhibitors, the chances of the disease recurring was 56 percent.
The researchers also noted the combination of beta-blocker and ACE inhibitor therapy , used to treat heart disease and control blood pressure, seemed to balance out any risk for women who had a history of breast cancer treatment.
Past studies show beta-blockers slow cancer spread
Beta-blockers have been suggested from past studies to slow the spread of breast cancer. Findings from Queen's Medical Centre, Nottingham University Hospital NHS Trust, published May 2010, studied 466 women already taking beta-blockers.
The findings, though small, linked beta-blockers to lower chances that breast cancer would metastasize and larger studies were recommended. The study, "Beta-Blocker Drug Therapy Reduces Secondary Cancer Formation in Breast Cancer and Improves Cancer Specific Survival", was published in the journal Oncotarget.
Beta-blockers inhibit stress-hormones. Scientists suspect they may protect from cancer spreading because studies in animals have shown stress can speed the rate of cancer spread, shown in a melanoma study from Ohio State University.
UCLA Jonsson Comprehensive Cancer Center researchers have also been studying the effect of stress and cancer spread in mice. A Sept 2009 study from the researchers showed beta-blockers could stop cancer metastasis in rodents.
Dr. Patricia Ganz, director of cancer prevention and control research the UCLA cancer center says, “We are learning that some medications, while they may be very helpful for treating cardiovascular disease and hypertension, may have an adverse effect on breast cancer survivors.”
In the current study, 292 women experienced recurrence of breast cancer - 23 percent of those had been exposed to either a beta blocker or an ACE inhibitor and many had other risk factors for disease recurrence including post-menopausal status, obesity, high blood pressure or diabetes.
The researchers are looking more closely at how ACE inhibitors might contribute to breast cancer recurrence by studying mouse tissue. From past studies, they have some understanding of how beta-blockers could protect women from breast cancer returning.
Ganz explains, Up until recently, there’s been a lot of focus on the cancer cell, but we need to understand that these malignant cells live in a microenvironment of growth signals and fat cells, insulin and inflammation, and these things may affect the way they behave.”
She says cancer cells do not live in isolation and a host of lifestyle factors, including medications, could affect breast cancer recurrence. Modifying lifestyle can lead to better outcomes for women treated for the disease - likewise, medication therapy could influence a woman's survival, based on the observations from the current study.
The findings from the LACE cohort study show women treated for breast cancer and taking ACE inhibitors, commonly used to treat blood pressure, may be at risk for recurrence of the disease. Stopping medication based on the study findings is not recommended. Beta-blockers, if there are no contraindications, may an option for concerned women that should be guided by a health care provider.
Breast Cancer Research and Treatment
"Examining the influence of beta blockers and ACE inhibitors on the
risk for breast cancer recurrence: results from the LACE cohort"
Patricia A. Ganz, Laurel A. Habel, Erin K. Weltzien, Bette J. Caan and Steven W. Cole
Image credit: Wikimedia commons
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