10 things to know about the intersection of breast cancer, CVD

When a woman receives a breast cancer diagnosis, she likely isn’t thinking about her heart health. But, experts at the American Heart Association (AHA) say, she probably should be.

This week, the AHA published a scientific statement detailing the cardiovascular risks that can come with cancer treatment. Rather than going full steam ahead with chemotherapy or radiation, clinicians are now suggesting patients and doctors work together to weigh their options before choosing a treatment path, taking into account how certain therapies could affect the patient’s overall well-being and, particularly, cardiovascular health.

Laxmi Mehta, MD, led the group of writers who ultimately published their formal recommendations in the AHA journal Circulation this week. This is what they said people should know about the intersection of breast cancer and heart health.

1. The two have more in common than you’d think.

Breast cancer and cardiovascular disease (CVD) share a number of risk factors, including older age, onset of menopause, low-quality diets, family history, hormone replacement therapy, obesity, lack of physical activity and alcohol and tobacco use.

While there aren’t many options when it comes to age and family history, Mehta et al. wrote patients can mitigate their symptoms by following the AHA’s “Life’s Simple 7” guidelines, which should reduce the odds of developing either condition.

2. Monitoring heart health is key before, during and after cancer treatment.

A cancer diagnosis is overwhelming, and it’s not easy to follow that news with warnings of CVD.

“Oncologists may tell women about potential risks, but patients are getting so much information they may not remember,” Seattle-based primary care internist Mary Ann Bauman, MD, said in an AHA release. “I have a family member who just finished her radiation for breast cancer, and I don’t want to scare her about potential cardiac effects of her treatment.”

Still, Mehta and co-authors said, doctors and patients alike need to recognize the importance of monitoring cardiovascular health throughout the process of cancer treatment to avoid any unexpected complications.

3. Breast cancer might be widespread, but it’s still not as big of a killer as CVD.

Both affect millions of women in the U.S. each year, but Mehta’s team wrote it’s a common misconception that cancer is more deadly than CVD. While 3.32 million women are affected by breast cancer across the country, 47.8 million women are affected by cardiovascular disease.

Early detection and improved treatments for breast cancer are increasing patients’ life spans, but that also means there will be more survivors who are at increased odds of developing CVD.

4. Older breast cancer survivors are more likely to die from heart disease than a cancer relapse.

It’s another common belief that a cancer relapse is more imminent than heart failure, but that’s not true, the authors wrote. Breast cancer survivors—especially those aged 65 and up—are actually more likely to die from CVD complications than another bout of cancer.

5. Genetics can play a role.

Though no single gene can predict simultaneous diagnoses of breast cancer and CVD, scientists have uncovered some genetic clues linked to cancer risk.

“Clinical and population-based studies have demonstrated that genetic factors play important roles in both breast cancer and CVD, and genes involved in the development of breast cancer and CVD have been identified,” Mehta and colleagues wrote. Two breast cancer susceptibility genes, known as BRCA1 and BRCA2, are thought to account for 5-10 percent of all breast cancer cases. Researchers have been able to use this information to create gene-targeted therapies for these patients, and genes involved in the development of CVD have been identified, but more work needs to be done.

6. Some chemotherapy drugs appear to increase CVD risk.

Doxorubicin, a common chemo drug, has been shown to lead to damage in heart cells, pushing patients toward heart failure. Administering doxorubicin more slowly can be both beneficial and protective, studies have shown, and result in lower rates of heart failure.

Anthracyclines, too, have been connected to the development of abnormal heart rhythms, which, if not benign, can lead to more permanent arrhythmia problems in cancer patients.

7. That also goes for certain radiation therapies…

Mehta and co-authors wrote that radiation in itself can encourage artery blockage and result in coronary artery disease. It’s also been shown to increase chances of cardiomyopathy, valvular disease, pericardial disease and arrhythmias.

8. ...and HER-2-targeted treatments.

HER-2 directed therapies are designed to combat particularly aggressive forms of breast cancer, but the treatments might be doing more harm than good, research has found. Certain therapies have been linked to weakened heart muscle, heart failure and left ventricular dysfunction.

9. Still, there’s promise in untapped markets.

Science is still working on combating the negative effects cancer treatment can have on patients’ hearts, but drugs that can reduce cellular damage are being slowly introduced to the medical market. One of these drugs, dexrazoxane, was recently approved for use in metastatic breast cancer patients who receive high doses of doxorubicin.

10. Preventive therapies exist.

There are certain medications individuals can take to preventively combat their risk of both CVD and breast cancer, the authors wrote. Beta-blockers, aspirin and statins are all familiar drugs that can reduce the risk of both illnesses, and certain non-medical treatments, like exercise, can make a big difference, too.

“As the population ages, there will likely be more women with breast cancer, CVD, or both,” Mehta et al. said. “With the evolving intersection of the cardiovascular and oncologic fields, comprehensive care is an essential element in the management of cancer patients to maximize gains in cancer treatment while minimizing the potential deleterious impact on cardiovascular health.”