By Anna Giorgi 

 Medically reviewed by Gagandeep Brar, MD

Patients who receive certain types of breast cancer therapies have a higher risk of getting heart disease than patients who were not treated for the disease. Research has shown that the link is often due to heart damage that occurs from certain cancer drugs and other treatments. These problems can range from high blood pressure to heart failure.¹

The link may also appear because both breast cancer and heart disease share risk factors. Many people with breast cancer may also have a higher risk of getting heart disease due to factors like poor diet, not getting enough physical activity, or smoking. These lifestyle risk factors often were there before they got breast cancer.²

This article describes the link between breast cancer and heart disease, the risks of having both diseases, factors involved in treating these conditions, and ways to prevent heart disease after having breast cancer treatment.

Anchiy / Getty Images

Connection Between Breast Cancer and Heart Disease

Advances in breast cancer treatments and earlier detection through screening have helped to improve the prognoses for people who are diagnosed with the disease. However, many therapies that help can extend and save the lives of people with breast cancer can also increase their risk of heart disease. This is especially important because heart disease is the leading cause of death among women in the United States.³

How Are They Connected?

While breast cancer can cause complications in the cardiovascular system (like a buildup of fluid around the heart), the link between breast cancer and heart disease is thought to be related to the therapies used to treat cancer rather than to the cancer itself.

Heart damage that occurs from cancer treatment is called cardiotoxicity. It can also affect the blood vessels, the immune system, and/or the heart muscle. This damage can increase your risk of stroke, heart attack, and heart failure.

Heart damage from cancer treatment can lead to:¹

• Left ventricular dysfunction

• Arrhythmia

• Heart failure

• Myocarditis

• High blood pressure

• Atrial fibrillation

• Atherosclerosis

Risks

People with early-stage breast cancer are often treated with a combination of surgery followed by treatments called adjuvant therapies. These treatments can include:

• Chemotherapy

• Immunotherapy

• Radiation therapy

• Targeted treatments

Adjuvant therapies try to get rid of every cancer cell in your body. Research has shown that using adjuvant systemic therapies can lower a person's risk of dying from breast cancer by at least 50%.⁴

However, some of these treatments also increase a person's risk of heart disease. The following adjuvant therapies are known to increase the risk of heart damage and heart disease in breast cancer patients:⁵

• Anthracyclines (e.g. doxorubicin, epirubicin)

• Alkylating agents (e.g. cisplatin, cyclophosphamide)

• Taxanes (e.g. paclitaxel)

• Antimetabolites (e.g. 5-fluorouracil, capecitabine)

• Endocrine therapy (e.g. tamoxifen, anastrozole, letrozole)

• HER-2–directed therapies (e.g. trastuzumab, pertuzumab)

• Cyclin-dependent kinase 4/6 inhibitors (e.g. ribociclib)

• Radiation therapy

Some forms of chemotherapy can also cause heart murmurs and heart rhythm issues, but these problems are usually temporary and only occur in the short-term period after treatment. Radiation therapy is more likely to affect long-term heart disease risk.²

People who receive radiation therapy for left-sided breast cancer have more than twice the risk of heart disease than those treated for right-sided breast cancer. This is because of the level of radiation exposure they receive close to the heart and its key structures.⁶

The risk of heart disease from certain adjuvant treatments might be lower for younger people with breast cancer because they generally have a lower risk of heart disease. However, the risk of heart disease increase with age for everyone.⁷

Older people with breast cancer who also have one or more of the following risk factors for heart disease may have a higher risk of developing heart disease after breast cancer treatment:⁸⁷

• Personal or family history of heart disease

• Obesity

• Diabetes

• High blood pressure

• Prior radiation therapy

• Prior treatment with anthracycline or other drugs that increase the risk of heart disease

The Reciprocal Effect of Heart Disease on Breast Cancer Recurrence

Breast cancer treatment increases the risk of heart disease, but there is also evidence of a reciprocal effect of heart disease on breast cancer.

One study of breast cancer survivors found that patients who had a heart attack or another cardiovascular event were more likely to have a recurrence of breast cancer. They were also more likely to die from breast cancer when it came back.⁹

Treatment and Management of Breast Cancer with Heart Disease

Treatment decisions for people with early-stage breast cancer are based on the size and location of the tumor. Treatment is intended to remove the tumor, get rid of breast cancer cells, and decrease the risk of recurrence.⁸

However, with the known risk of heart disease, healthcare providers consider a patient's risk based on a cardiovascular evaluation and their personal and family history.

In most cases, you and your providers must weigh the need to use certain medications to treat and eradicate the type of breast cancer you have against the chances of developing future heart disease or worsening a pre-existing heart condition.

For example, anthracycline doxorubicin is a very effective form of chemotherapy for breast cancer, but it has the potential to cause irreversible heart damage. While other drugs may pose less risk of heart disease, they may offer you the best chances against breast cancer spread or recurrence. In some cases, modifying the dosage of a preferred treatment can help lower your risk of heart disease while also allowing you to gain its benefits.²

With radiation therapy, certain strategies like deep inspiration breath holding can help minimize the amount of radiation that affects the heart. This technique involves inhaling a deep breath and holding it during radiation to use your full lungs to create distance between your breast and your heart. Radiation can also be administered while you lie on your stomach. This allows your breasts to hang away from your heart and reduce the amount of radiation that affects it.²

If your heart muscle weakens during breast cancer treatment, you may need to stop treatment and allow your heart to recover. If the heart damage is severe, it could jeopardize the use of any adjuvant therapy.¹⁰

If your breast cancer treatment increases your risk of heart disease, you can expect to undergo regular heart health screenings. The type and frequency of heart monitoring during breast cancer treatment vary based on the type of therapy you receive and your heart health.

One or more of the following tests might be used to monitor your heart health before, during, and/or after breast cancer treatment:

• Electrocardiogram

• Echocardiogram

• Endomyocardial biopsy

• Cardiac magnetic resonance imaging (MRI)

• Cardiac biomarkers

What Is Cardiooncology?

A new field of medicine is cardiooncology (also called cardio-oncology). Providers work with patients to address both their cardiovascular health (cardiology) and cancer care (oncology) needs.

Prevention

The development of heart disease as a result of breast cancer is not inevitable. You can take steps to reduce your risk of both diseases at once. It's possible to reduce the risk of heart disease by living an overall healthy lifestyle and taking the following steps:⁷

• Exercising regularly

• Eating a nutritious diet with lean protein and fresh fruits and vegetables

• Not smoking or using tobacco products or quitting if you do

• Establishing and maintaining a healthy weight

• Limiting alcohol

• Controlling high blood pressure, high cholesterol, diabetes, or other chronic health problems

Some types of heart damage from breast cancer treatment are short-term. Others do not develop until well after treatment ends. Heart disease associated with radiation has a latency of at least five years.⁶ In the long term, breast cancer survivors may need a schedule of screenings for heart disease.

You can help prevent the serious consequences of heart disease by monitoring your symptoms and reporting any changes to your healthcare provider as soon as you notice them. Look for these early signs of heart disease:¹¹

• Dull, heavy, or sharp pain in the chest (angina)

• Pain in the neck, jaw, or throat

• Pain in the upper abdomen or back

• Fatigue

• Nausea or vomiting

• Shortness of breath

• Swelling in the veins in your feet, ankles, legs, abdomen, or neck

• Palpitations in your chest

Following your recommended schedule of check-ups and screenings can help identify heart disease as early as possible and start treatment when it will be most effective. It may also help prevent the recurrence of breast cancer after your treatment is complete.⁹

Summary

Having certain types of breast cancer treatments can give you a higher risk of heart disease compared to people who were never treated for breast cancer. Research has shown that some breast cancer treatments can damage blood vessels, the heart, and the immune system. The effect can cause heart disease, ranging from problems like high blood pressure to heart failure.

The link between these conditions may also be tied to the fact that they share some risk factors. The things that can make some people more likely to get breast cancer can also increase their risk of heart disease—for example, a poor diet, smoking or using tobacco, and having obesity. Being older and/or having a family history of heart disease can also affect your heart disease risk.

Reducing risks and tracking heart health with imaging can help most breast cancer patients treat their disease and reduce their risk of heart disease.

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By Anna Giorgi
Anna Zernone Giorgi is a writer who specializes in health and lifestyle topics. Her experience includes over 25 years of writing on health and wellness-related subjects for consumers and medical professionals, in addition to holding positions in healthcare communications.