Women who have had breast cancer are living longer than ever before. By eight years after a breast cancer diagnosis, people without metastatic disease are more likely to die from heart disease than breast cancer. Breast cancer treatment can increase the risk of some diseases of the heart, arteries and blood vessels, also known as cardiovascular diseases (CVD).

Who is at risk?

CVD and breast cancer share many risk factors. A family history, our genes, and getting older increase the risk of both. Diabetes and high blood pressure are linked to CVD. Women with breast cancer are more likely to develop high blood pressure and diabetes compared with those never diagnosed with breast cancer. Those who have high blood pressure or diabetes before breast cancer have twice the risk of heart problems after breast cancer.

Several things that we may be able to control also contribute to both CVD and breast cancer, including not moving enough (lack of physical activity), eating lots of red meat, drinking too much alcohol, and smoking or vaping tobacco. Breast cancer treatments, such as chemotherapy, radiation, and medicines, can also impact heart health, even years later.

Zero Breast Cancer researcher partners, Dr. Heather Greenlee of the Fred Hutchinson Cancer Research Center and Dr. Marilyn Kwan at Kaiser Permanente Northern California’s Division of Research, have been leading a study of CVD in women who have had breast cancer compared to those who have not. They found that:

• Women who received chemotherapy are more likely to develop problems with the heart’s pumping (heart failure, which doesn’t mean the heart stops), diseases of the heart muscle (cardiomyopathy), or a blood clot that starts in a vein (venous thromboembolism).
• Women who received left-sided radiation were more likely to develop problems with the heart’s pumping (heart failure), or a blood clot that starts in a vein (venous thromboembolism).
• Women who received hormonal therapy were more likely to have their heart stop pumping (cardiac arrest) or develop a blood clot that starts in a vein (venous thromboembolism).

Radiation can harden or stiffen the heart tissue and chemotherapy drugs can damage the heart. A common chemotherapy drug, doxorubicin (Adriamycin®), is known to increase the likelihood of heart problems. It can cause changes in heart rhythm (arrhythmias) or reduce the pumping action (heart failure). Another drug, trastuzumab (Herceptin®) is used to treat HER2-positive breast cancers (about 1 in every 4 breast cancers). It can cause heart muscle damage and heart failure; these problems usually go away when women stop taking Herceptin®.

The risk of heart problems and of breast cancer can also be affected by other things, like air pollution from traffic and smoke where we live, work and play (also known as our social and built environment). Drs. Salma Shariff-Marco and Scarlett Lin Gomez, our partners at the University of California-San Francisco, are exploring how our social and built environments impact CVD risk after breast cancer. These scientists are working to predict who is likely to have heart problems from their breast cancer treatment to improve prevention and treatment.

Reducing the risk of Heart Disease

Some healthy habits can keep your heart strong, reduce your risk of a breast cancer recurrence, and help your heart heal if you have a heart condition:

• Eating healthy
• Physical activity and moving often
• Not smoking or vaping tobacco
• Limiting alcohol
• Managing stress

Sometimes during breast cancer treatment or with other health problems, we may not be able to exercise. On days that we have some energy, even small amounts of physical activity can help. For those of us who have not been active recently, cancer exercise experts say we should “start low and go slow”; that is, begin with shorter amounts of easier movement, like walking and light weights, and build up gradually. Breast cancer survivors who got 150 minutes of moderate-intensity activity per week had fewer CVD events (23% less) than those who were not active.

Eating healthy is also important. Avoiding red meat and eating a diet of whole grains, vegetables and fruits that is low in fats and sugars, can lower both CVD and breast cancer risk. Maintaining a healthy weight is good, however, losing too much weight or too quickly can be a sign of a problem. Check out our blog for advice on eating well and being active. 

Managing stress is also important for heart health, including getting enough sleep and keeping relationships strong. For tips, see our blog on connecting with ourselves and others. 

What are CVD Signs and Symptoms?

Some common warming signs of heart problems are:

• Shortness of breath (with activity or lying down)
• Swelling of feet and lower legs (edema)
• Feeling weak or dizzy
• Fatigue
• Chest pain

Women may feel that their heart is beating irregularly, very fast, or forcefully in their chest, nausea/vomiting, and/or back or jaw pain.

You can learn about common heart conditions on the CDC Heart Disease website. If you have concerns about your heart health, talk to your primary care doctor or nurse practitioner. For help asking questions, check out these tips for talking to a doctor.