Heart health

Heart problems are a rare but serious side effect of some medicines used to treat breast cancer. These medicines can damage the heart muscle and its ability to pump blood as well as it should.

What are the symptoms of heart damage?

Damage to the heart can result in signs of mild heart failure, such as shortness of breath, or it can show no symptoms at all. In some cases, heart damage is severe enough to cause:

• Stroke
• Cardiomyopathy, in which the heart muscle cannot contract
• Congestive heart failure, in which the heart can’t pump enough blood to give the body the oxygen and nutrients it needs

If you are having heart problems, you may have one or more of these symptoms:

• Shortness of breath
• Chest pain
• Pressure in the chest when lying flat
• Swelling in the hands, feet, ankles, or legs
• Fatigue
• Persistent or dry cough
•  Nausea
• Increased or irregular heart rate
• Dizziness

Symptoms may appear during treatment or weeks or months after treatment ends. Mild heart damage may not show any symptoms and may only be found through a heart test called an echocardiogram, which looks at the heart's function and structure.

What causes treatment-related heart problems?

Heart problems are a side effect of some chemotherapy and targeted therapy medicines used to treat breast cancer.

Certain medicines are more likely to cause heart problems than others:

• Some chemotherapy treatments, especially anthracyclines such as doxorubicin (Adriamycin) and epirubicin (Ellence), can cause heart damage. Heart damage is often related to the total amount of chemotherapy you receive in your lifetime. For most chemotherapies, there is a maximum amount you can get over the course of your life, and then you have to stop.
• Radiation therapy for breast cancer sometimes has a risk of heart damage. When the heart is exposed to radiation, there is an increased risk for heart complications such as cardiac fibrosis, an abnormal thickening or forming of scar tissue on the heart valves. Radiation treatment to the left breast, which is closest to the heart, also increases your risk for heart disease. A technique called deep inspiration breath hold can help reduce the risk of heart damage caused by breast cancer radiation therapy.
• Some hormonal therapies have a risk of causing heart problems, including aromatase inhibitors, which can increase the risk for coronary artery disease. Tamoxifen can increase the risk of blood clots that can lead to stroke.
• Some targeted therapies that treat HER2-positive breast cancer increase the risk of heart damage, including:
  • Ado-trastuzumab emtansine (Kadcyla)
  • Neratinib (Nerlynx)
  • Pertuzumab (Perjeta)
  • Trastuzumab (Herceptin) and biosimilars targeting the HER2 receptor

Remember, not everyone who takes these medicines develops heart problems, and symptoms and severity can vary among those who do. Older people have a higher risk of developing heart problems from chemotherapy.

Heart problems can also be caused by lifestyle factors such as smoking, being overweight, eating foods high in fat and cholesterol, and not exercising enough.

Another medicine, bevacizumab (Avastin), is no longer FDA approved for breast cancer treatment. If you were treated with bevacizumab in the past and are concerned about your heart health, talk with your oncologist.

How can I lower my risk of heart problems?

Before you start treatment, talk with your care team about existing and past health problems. Let them know if:

• You have a history of heart disease
• You've been treated with chemotherapy in the past
• You've been treated with radiation therapy to the chest in the past

Your care team will perform tests to evaluate your heart function before you start treatment. During treatment, your heart will be closely monitored, especially if you have a history of risk factors. As part of this, your care team may look at left ventricular ejection fraction (LVEF), or the volume of blood pumped out of the heart with every beat. Low LVEF suggests serious heart problems.

Heart function tests may include:

• Echocardiograms, which record electric currents created by your heart and shows doctors your heart function, including LVEF
• MUGA scans, which create video images of the lower chambers of the heart and checks the movement of blood through the heart, which includes LVEF

Talk to your doctor right away if you have chest pain, breathing problems, or any other symptoms of heart trouble during and after your treatment. Heart problems can be caused by many things, so knowing if your cancer treatment is affecting your heart is important. Cardiotoxicity, or damage to the heart muscle, needs to be treated quickly before the damage becomes severe.

How can I manage symptoms and keep my heart healthy?

Let your care team know immediately if you experience symptoms of heart problems. If they believe your treatment is causing the symptoms, they may lower the dose of the medicine causing them, give them differently, or stop treatment with that medicine.

If you're having heart symptoms, here are some other options your care team may discuss with you:

• In some cases, you may be able to manage symptoms by taking medicines that remove extra fluid from your tissues or that treat heart failure, such as angiotensin-converting-enzymes (ACE inhibitors) or beta-blockers. Researchers are looking at whether ACE inhibitors and beta blockers may protect the heart if given before cancer treatment.
• If you have severe shortness of breath, oxygen therapy can be given.
• Taking heart-strengthening medicines often brings heart function back to normal within a few weeks.

Here are some tips to keep your heart healthy during treatment:

• Manage stress. Try complementary therapies such as yoga, Mindfulness-Based Stress Reduction (MBSR), massage therapy, guided imagery, or deep breathing to keep your stress level low.
• If you smoke, quit smoking. If you need to, talk with your care team about ways they can help you quit smoking.
• Stay away from secondhand smoke.
• Exercise to help you feel more energetic, lessen side effects such as fatigue, and keep your heart healthy and strong. Ask your care team about ways to safely and comfortably fit exercise into your care plan.
• Eat healthy, nutritious food. Reduce salt and fat in your diet. Ask your care team about other foods to include or limit. You can also ask to be referred to a nutritionist who can help give you strategies for eating well to protect your heart.
• Avoid alcohol or drink in moderation (limited to 1-3 drinks a week).
• Watch your weight. Being overweight or obese causes your heart to work harder and increases the risk of heart disease. It may also increase the risk of other health problems, including diabetes and certain cancers.
• Work with your care team to monitor your cholesterol level and blood pressure.

Should I see a heart specialist after treatment ends?

Once your treatment ends, you may still be at increased risk for heart problems because of treatment or personal risk factors. In the U.S., heart disease is the leading cause of death for women and men, so it's important to have your heart function monitored on a regular basis. Be sure to discuss this with your doctor.

The National Comprehensive Cancer Network (NCCN) recommends heart monitoring for people who received anthracycline chemotherapy, radiation therapy to the left breast, and HER2-targeted therapy, because these treatments are known to impact heart health. They recommend that people who receive these treatments:

• Be checked regularly for heart health risk factors
• Discuss their cancer and treatment history with their heart specialist, if they already see one
• Discuss diet and exercise habits with their doctor

If you had a heart issue before starting treatment for cancer, your oncologist may refer you to a cardiologist or onco-cardiologist after cancer treatment ends. The NCCN recommends that anyone considered high risk for developing heart issues should be screened for heart failure within the first year after anthracycline treatment ends.

Heart health and metastatic breast cancer treatment

Long-term treatment for metastatic breast cancer (MBC) may increase the risk of heart problems. Certain treatments are known to cause heart damage, so talk with your care team about regular tests to check your heart function.

Here are the MBC treatments that have heart risks:

• Aromatase inhibitors, approved to treat hormone receptor-positive breast cancer, increase the risk of coronary artery disease.
• High doses of certain chemotherapy medicines, especially anthracyclines such as doxorubicin (Adriamycin), can weaken the left ventricle, the heart’s main pumping chamber, which can lead to heart failure.
• Some targeted therapies that treat MBC can cause heart problems:
  • Ribociclib (Kisqali), a CDK 4/6 inhibitor approved to treat hormone receptor-positive, HER2-negative MBC, can cause irregular heart rhythm.
  • Olaparib (Lynparza), a PARP inhibitor approved to treat HER2-negative MBC that is either hormone receptor-positive or negative in people who have tested positive for a BRCA mutation, can cause fast or irregular heartbeat.
  • Some targeted therapies approved to treat HER2-positive MBC can damage the heart muscle. These include:
    • Ado-trastuzumab emtansine (Kadcyla)
    • Lapatinib (Tykerb)
    • Margetuximab (Margenza)
    • Neratinib (Nerlynx)
    • Pertuzumab (Perjeta)
    • Trastuzumab (Herceptin) and biosimilars targeting the HER2 receptor
    • Trastuzumab deruxtecan (Enhertu)
    • Tucatinib (Tukysa)

Before you start treatment, tell your doctors about any heart problems you’ve had in the past, or if you have any health history that puts you at risk for heart problems, such as a family history of heart disease. Ask your care team about nutrition and safe exercise during cancer treatment, because both support your heart health.

Before and throughout treatment, be sure to tell your doctors if you experience any of the symptoms of heart damage described above, such as shortness of breath; swelling in hands, feet, ankles, or legs; persistent or dry cough; or increased or irregular heart rate.

Your care team will regularly monitor your heart function, help you manage any heart symptoms, and share guidance on preventing heart damage. If tests show your treatment is causing heart problems, your doctor may:

• Recommend medicines to manage symptoms and strengthen your heart
• Lower the dose of the medicine causing heart problems
• Give you the treatment less often
• Give you a treatment break, in which you temporarily stop treatment with the medicine causing heart problems in order to ease symptoms
• Switch you to a different cancer treatment to stop symptoms from getting worse

Most treatment guidelines include recommendations about lowering the dose or changing the treatment schedule if side effects become hard to manage. If these kinds of changes would result in less effective treatment, your healthcare team would recommend a different treatment.

It's completely understandable to be concerned about treatment-related heart damage and the risk of heart attack, especially if you have a family history of heart disease. It's important to know that symptoms of a heart attack can be different for different people, but can include:

• Feelings of pressure, pain, or squeezing in the chest that last longer than a few minutes
• The feeling that your heart is skipping a beat (palpitations)
• Discomfort or pain in shoulders, arms, neck, teeth, or jaw
• Stomach pain that feels like heartburn
• Anxiety or panic
• Nausea and vomiting
• Sweating
• Dizziness

If you experience these symptoms and feel that you may be having a heart attack, dial 911 or go to the nearest emergency room.