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Written by: Cameron Rosario
Medically reviewed by: Robert Philibert MD PhD

The American Cancer Society (ACS) predicts that in the United States, 13% of women will develop breast cancer. Fortunately, over the past two decades the survival from breast cancer has increased dramatically.  But for those who survive, it is important to remember that heart disease is the leading non-cancer cause of death.  As a consequence, understanding how breast cancer and its treatment may modify your risk for heart disease is critical for planning a comprehensive health care strategy for those with breast cancer.

Treatments For Breast Cancer That May Affect The Heart

The heart is very active metabolically.  As a result, there are a number of ways in which treatment of breast cancer could affect your risk for heart disease. Perhaps the best understood are the effects of commonly used breast cancer treatments on the heart. For example:

  • Chemotherapy Medications
    • Common chemotherapy medications, such as Doxorubicin (adriamycin), may cause heart damage. Doxorubicin and similar acting drugs work by inhibiting DNA and RNA synthesis, which in turn stops cells from dividing at a rapid rate. Though this is very effective for killing the rapidly dividing cancer cells, it may come with irreversible damage to the heart. Some potential effects include heart failure, high blood pressure, blood clots, and abnormalities in heart rhythm. Your risk for developing heart problems following chemotherapy is dependent on the health of your heart before treatment, the specific drug used, drug dosage, and if the drug is used in  conjunction with other drugs. However, though effective, Doxorubricin is a very old drug. It was first introduced in 1974.  Since that time, less toxic and sometimes more effective breast cancer treatments have been developed.  Here is a list of some of these agents and their possible effects on the heart.

Table 1: A list of chemotherapy agents and their corresponding potential cardiovascular effects 

Chemotherapy Agent  Possible Cardiovascular Effect 
arsenic trioxide (Trisenox) Q-T prolongation
bevacizumab (Avastin) Severe hypertension, heart failure, cardiomyopathy, thromboembolism
bortezomib (Velcade) Edema
cisplatin (Platinol) Severe hypertension, ischemia, atrial fibrillation, thromboembolism
doxorubicin (Adriamycin) and other anthracyclines Cardiomyopathy, heart failure, cardiac shock
fluorouracil 5-FU (Adrucil) Ischemia
imatinib (Gleevec) Edema
interleukin-2 (Proleukin) Atrial fibrillation
lapatinib (Tykerb) Q-T prolongation
lenalidomide (Revlimid) Thromboembolism
melphalan (Alkeran) Atrial fibrillation
mitomycin (Mutamycin) Heart failure
mitoxantrone (Novantrone) Heart failure
pazopanib (Votrient) Hypertension
sorafenib (Nexavar) Hypertension, heart failure, thromboembolism
sunitinib (Sutent) Hypertension, heart failure, thromboembolism
thalidomide (Thalomid) Thromboembolism, bradycardia, edema
trastuzumab (Herceptin) Heart failure


    • Radiation Therapy 
      • Like chemotherapy medications, radiation therapy can be very effective in treating cancer. Yet, its use can result in  damage to the heart. Like doxorubicin, radiation therapy exerts its effects through damaging DNA, in this case inducing double strand breaks, in tumor cells.  But due to the proximity of the heart to the breast, it is very difficult to limit the effects of the radiation beam to just the cancerous cells.   This off-target damage to the heart is often evident within a few years, reducing the patient’s quality of life and increasing an individual’s risk for heart disease. Radiation can damage almost all portions of the heart including the pericardium, myocardium, heart valves, myocardium, and coronary arteries. The resulting damage can cause arrhythmias (irregular heartbeat), congestive heart failure, cardiomyopathy (heart muscle disease), myocarditis (inflammation of the heart muscle), heart valve disease, pericarditis (inflammation of the fibrous sac surrounding the heart), and premature coronary artery disease (major cause of heart attacks).
      • It is often difficult to detect these effects directly.  Instead, patients and their health care providers should closely monitor for early potential signs of treatment induced heart disease, such as high blood pressure or high cholesterol.

Be Aware of the Symptoms

After receiving chemotherapy or radiation therapy, it is important to be aware of the symptoms that indicate future heart disease. It is advised to work closely with your primary health care providers to help monitor symptoms and early signs of heart disease.

      • Shortness of Breath (SOB): A feeling that you are not getting enough oxygen.
      • Tachy or bradycardia;heart beat: When your heart beats above or below, respectfully, the normal range of 60-100 beats per minute.
      • Frequent coughing,.
      • Swelling of feet and lower legs: The inflammation or accumulation of fluid resulting in the overall enlargement of your feet or lower legs. Sometimes accompanied by a tender feeling in these areas.
      • Lightheadedness: The feeling as if you are about to faint or fall over.
      • Fatigue: An overall feeling of immense tiredness and lack of energy.

Breast Cancer Prevention

Therefore, there are some ways you can optimize your health to help insure a healthy recovery:

      • Physical Activity
        • There are consistent studies demonstrating the beneficial relationship between physical activity and diseases like breast cancer and heart disease. In a 2019 systematic review, breast cancer survivors were shown to have a 42% lower risk of death from any cause and a 42% lower risk of death pertaining to breast cancer compared to women who were not physically active. Physical activity has been shown to reduce the risk of breast cancer related heart injury. Exercising for 30-40 minutes, 5 times a week, is recommended for women who are receiving breast cancer treatment.
      • Diet
        • Maintaining a healthy diet can strengthen the surveillance of the immune system for cancerous cells.  The current generation of therapies for breast cancer often rely on increasing the activity of cancer fighting lymphocytes (a type of immune cell).  These white blood cells need adequate supplies of key nutrients, such as B vitamins, to do their job well.  Eating a healthy diet that contains green leafy vegetables helps supply these nutrients and is also part of a heart healthy diet.
      • Visit Your Oncologist
        • Listening to your oncologist and following your treatment plan is the best way you can maximize your health. Engaging in conversations regarding your risk, side effects of chemotherapy, and getting regular heart-health screening tests can help you plan out your next steps to remain as healthy as possible.