Cardiovascular disease is the No. 1 killer of both men and women in America today. The Centers for Disease Control and Prevention reports that 610,000 people die of heart disease each year, which amounts to a quarter of all deaths. By comparison, the National Institutes of Health estimates that 40,610 women died of breast cancer in 2017, making it the second deadliest cancer among women. ( Lung cancer claims the top spot.) Although improved screening and treatment for breast cancer has made the disease less likely to kill, these treatments can sometimes cause damage to the heart and must be managed carefully to avoid increasing a patient’s risk of developing heart disease later.
Doctors and researchers take the potential cardiotoxicity of breast cancer treatments seriously. In February 2018, the American Heart Association released a scientific statement addressing the intersection of breast cancer treatment and cardiovascular disease, which pointed to some of the systemic therapies used to combat breast cancer as having a detrimental impact on heart health. Although a very large new study in the European Heart Journal found that the risk of death from heart disease in women who’ve been treated for breast cancer isn’t actually higher than it is in the general population, several treatments for breast cancer can still cause damage to the heart. The study cited good risk management by doctors and hospitals as being the reason that risk of death from cardiovascular disease in breast cancer patients isn’t higher. The AHA statement aims to underscore the importance of heart health management in breast cancer patients and to alert doctors and patients to the potential overlap between the two diseases.
Dr. Laxmi S. Mehta, lead author on the AHA statement and section director of preventive cardiology and women’s cardiovascular health at the Ohio State University Wexner Medical Center, says “there’s growing data that more women are surviving breast cancer, which is great, but managing their other cardiac risk factors is really essential in affecting their outcome. We know that women who survive breast cancer, especially the older breast cancer survivors, are more likely to die from cardiovascular disease,” and that the very treatments used to save their lives from breast cancer could cause damage to the heart.
[See: Breast Pain? Stop Worrying About Cancer.]
There are several potential culprits including chemotherapy, radiation treatment and some targeted therapies. “We’ve known for a long time that some chemotherapy drugs can have direct effects on the heart,” says Dr. Dawn L. Hershman, professor of medicine and leader of the breast cancer program at the Herbert Irving Comprehensive Cancer Center at New York-Presbyterian Columbia University Medical Center. These drugs may elevate a patient’s “risk for developing congestive heart failure. Some of those drugs include chemotherapy drugs like Adriamycin,” and other drugs in the anthracycline and taxane classes of chemotherapies. Some of these drugs can weaken heart muscle cells or alter the heart’s normal rhythm. Some of the newer, HER2-targeted therapies like Herceptin [trastuzumab] and Perjeta [pertuzumab] may also affect the heart directly,” causing arrhythmias, valve problems, blood clots, enlargement of the heart or heart failure, Hershman says. These targeted therapies are used to treat HER2-positive breast cancers, where a protein called HER2/neu is overexpressed by the tumor.
Dr. Karol Watson, director of the UCLA Barbra Streisand Women’s Heart Health Program at the David Geffen School of Medicine, says that heart disease seldom results solely from a single source, even chemotherapy, but rather tends to be a more cumulative process. Watson was a co-author on the AHA statement and says radiation therapy — especially in patients with breast cancer in the left breast, which sits right over the heart — can also cause damage to the heart.
In addition to radiation and drug therapies that may have a direct impact on the heart, Hershman says there are also “a lot of indirect effects on cardiovascular risk,” during treatment for breast cancer. “Women who undergo treatment have a tendency to go into early menopause and that can cause weight gain and changes in their cholesterol levels,” as well as a reduction in physical activity, all of which may also contribute to the development of diabetes, another risk factor for cardiovascular disease. “Those kinds of changes to cardiovascular risk factors can increase their risk of developing cardiac disease down the line and are much more common than the direct toxic effects of the treatments we give.”
Taken all together, these risks build into the “multiple-hit theory” for cardiovascular disease risk, Watson says. “Cardiotoxicity falls under the rubric of the multiple-hit hypothesis. It’s unlikely that you’re going to get cardiotoxicity from any one thing, even if it’s as noxious as chemotherapy. Cardiotoxicity usually happens in the setting of multiple hits,” and these hits can take many forms, including elevated blood pressure, a history of smoking, having had radiation treatment and obesity. “Chemotherapy clearly damages the heart, but there are the other less obvious hits, and so trying to limit that second hit when you know you’re going to have that big hit” of chemotherapy can be an effective strategy for reducing your overall risk. This means getting control of your blood pressure and making sure your cholesterol levels are in check. Preventing weight gain, eating right and making sure you’re getting as much exercise as possible are also important.
[See: The 10 Best Diets for Healthy Eating.]
Mehta notes that when dealing with the stress of treatment for breast cancer, “often patients revert to poor dietary habits. We want to encourage them to eat properly.” She also recommends following up with your family doctor “even if you’re seeing an oncologist,” to keep tabs on other aspects of your health.
This is important, Hershman says, because “for many women, once they’re diagnosed with cancer they forget that they need anything else with regard to primary care because the focus is on breast cancer. So maybe they stop going for regular checkups with their primary care doctor.” Doing so can be bad for overall health and longevity so she recommends keeping on top of all aspects of your health and to keep open lines of communication with your various doctors.
In addition to controlling what lifestyle factors you can and staying on top of your general health, your doctor will keep tabs on your heart health and may alter your treatment schedule or add other medications as needed. Watson says some medications that have long been used to treat heart failure, including ACE inhibitors and beta blockers, may help protect your heart from chemotherapy-induced cardiotoxicity before it even occurs. Statins, which are typically used to lower cholesterol levels in the blood, may also have a protective effect on the heart in breast cancer patients. Some of the breast cancer–related cardiotoxicities are permanent while others are reversible, so your doctor may adjust your therapy schedule depending on whether your heart health changes during treatment.
During treatment for breast cancer and beyond, your doctor will monitor your heart health by checking your blood pressure and cholesterol levels and by taking echocardiograms — images of the heart that help the doctor see the structure — on a regular basis. Most patients get an echocardiogram every three months or so during treatment. Your doctor will also monitor your heart health for the rest of your life as heart problems may develop years after active treatment for breast cancer has concluded.
[See: 7 Surprising Things That Age You.]
Overall, trying to limit the number of “hits” your heart health takes over your lifetime should be part of your strategy to avoid a range of illnesses later in life, whether you have breast cancer or not. Watson says researchers and doctors have done “a much better job of identifying strategies for prevention” of cardiovascular disease, but that the cancer community is catching up. “Cardiovascular disease is largely preventable, and a good portion of breast cancer cases are preventable, too. The good news is that many of the things that prevent heart disease also prevent breast cancer,” with one notable exception. “We think moderate alcohol is protective against cardiovascular disease but all the data shows that even minimum to moderate alcohol intake increases breast cancer risk.”
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Can I Reduce the Risk of Heart Disease From Breast Cancer Treatment? originally appeared on usnews.com
