Cardiotoxicity: Cancer Treatment and the Heart

What is cardiotoxicity?

Cardiotoxicity is heart damage that arises from certain cancer treatments or drugs. It can develop years after cancer treatment, especially in adults who received cancer treatment during childhood. Certain types of cancer treatments have a higher risk for cardiotoxicity.

Cardiotoxicity may make it harder for your heart to pump blood throughout your body as it should. In severe cases, it may lead to cardiomyopathy, a heart muscle condition that makes it harder for your heart to pump blood.

Who does cardiotoxicity affect?

Cardiotoxicity can affect anyone who has had cancer treatment. It is more likely in those who have taken specific drugs or had radiation therapy to the chest.

It’s also somewhat common in adults who had cancer treatment as a child. It’s difficult to determine the exact rate of cardiotoxicity in adults who had cancer treatment as an adult. But, some groups estimate up to 20% of this population may develop heart problems, with up to 7% to 10% having cardiomyopathy or heart failure.

How does cardiotoxicity affect my body?

Cardiotoxicity may cause several heart problems, including:

• Cardiomyopathy.
• Heart attacks (myocardial infarctions).
• Coronary artery disease.
• Heart failure.
• Heart valve disease.
• Irregular heart rhythms (arrhythmia).
• Fluid buildup around the heart.
• Low or high blood pressure.
• Slow heart rate.
• Thickening of the heart’s lining (constrictive pericarditis).

What are the symptoms of cardiotoxicity?

Symptoms of heart problems related to cardiotoxicity may include:

• Abdomen enlargement (abdominal distension).
• Chest pain.
• Dizziness.
• Heart palpitations.
• Shortness of breath (dyspnea).
• Swelling and fluid retention (edema) in the legs.

What causes cardiotoxicity?

Certain cancer treatments may cause cardiotoxicity, including:

• Anthracyclines, such as doxorubicin (Adriamycin®), chemotherapy medications often used to treat leukemia, lymphoma, breast cancer, sarcoma or multiple myeloma.
• Trastuzumab (Herceptin®), a targeted therapy drug commonly used to treat breast cancer, stomach cancer or cancer of the gastroesophageal junction, where your food pipe (esophagus) connects to your stomach. This is most likely to cause cardiomyopathy if it’s combined with an anthracycline medication.
• Radiation therapy to the chest, often used to treat breast cancer or leukemia.

How is cardiotoxicity diagnosed?

Healthcare providers may diagnose cardiotoxicity by measuring the pumping function of your heart using left ventricular ejection fraction (LVEF) and evaluating the function of your heart valves. LVEF measures how much blood pumps out of your lower left heart chamber (left ventricle) each time your heart contracts.

They use certain tests to measure the heart’s pumping function and valve function, including:

• Echocardiogram: This is the most common imaging tool in cardiotoxicity diagnosis. Echocardiograms use electrodes and ultrasounds to check your heartbeat and view blood flow through your heart.
• Cardiac MRI: Some experts consider cardiac MRI the gold standard for detecting cardiotoxicity. It uses magnets, radio waves and a special computer to create detailed images of your heart’s structures and to evaluate how blood flows through your heart.
• Cardiac stress test: This test measures how your heart responds to intense activity. You may walk on a treadmill or ride a stationary bike while connected to a machine that measures your heart rate and blood pressure.
• Multigated acquisition scan (MUGA): This test evaluates the function of your heart’s ventricles. It uses a safe radioactive tracer that shows up clearly on an imaging scan. Your provider evaluates how the tracer moves through your bloodstream and calculates your ejection fraction.
• Cardiac CT scan: CT scans use many X-rays from multiple angles to get a detailed picture of your heart. This test may be most useful for people who have suspected cardiotoxicity after radiation therapy to the chest.

How is cardiotoxicity treated?

Your healthcare provider may recommend stopping certain medicines or decreasing their doses, depending on your current medication regimen. Your provider may also prescribe medications to help your heart work more efficiently, such as:

• ACE inhibitors, such as lisinopril (Zestril®) or fosinopril sodium (Monopril®), to open your arteries and improve blood flow.
• Beta-blockers, such as metoprolol (Lopressor®) or atenolol (Tenormin®), to increase blood flow and slow your heart rate.
• Digoxin, also called digitalis (Lanoxin®), to slow your heart rate and help it beat more efficiently.
• Diuretics, such as furosemide (Lasix®), to rid your body of excess fluid.
• Vasodilators, such as isosorbide dinitrate (Isordil®), to open up (dilate) your blood vessels so that blood flows more efficiently.

Can cardiotoxicity be reversed?

Cardiotoxicity may be reversible. Research has shown that cardiotoxicity that arises after using trastuzumab may be reversible. Cardiotoxicity that arises from anthracycline use is often not reversible and requires long-term treatment. Cardiotoxicity related to chest radiation is also very difficult to reverse and may require long-term treatment, possibly even surgery.

How can I reduce my risk of cardiotoxicity?

There’s no way to prevent cardiotoxicity. It’s important to discuss the potential health risks and benefits of treatments with your provider if you’ve been diagnosed with cancer.

You may increase your chances of catching cardiotoxicity early by undergoing regular heart imaging during cancer treatment. Detecting heart problems early may increase your chances of successfully treating them.

When should I see my healthcare provider?

Call 911 and go to your nearest emergency center if you experience any symptoms of a severe heart complication, such as:

• Persistent or ongoing heart palpitations or feeling like your heart is racing.
• Dizziness, lightheadedness, or passing out.
• Rapidly worsening shortness of breath or chest pain.
• Swelling of your throat or lips.
• Unusual swelling in your legs or feet.
• Weight gain of more than 3 pounds in one week.