Cardiotoxicity

What Is Cardiotoxicity?

Damage to the heart caused by cancer treatment is called cardiotoxicity. Certain drugs used in chemotherapy can cause cardiotoxicity. Radiation therapy to the chest also can damage the heart and the entire blood vessel system.  

In the last 20 years, improvements in cancer treatments have increased cancer survivor rates. These treatments also have caused an increase in heart-related side effects. Heart damage caused by cancer treatment affects between 10% and 20% of cancer survivors. Childhood cancer survivors can have five times the risk for developing heart issues within five to 10 years after chemotherapy.

Cardiotoxicity weakens the heart. A weakened heart can lead to serious heart problems if not caught early and treated.

Types of Heart Problems Caused by Cardiotoxicity

According to the American Cancer Society, cancer survivors have a 52% higher risk of developing heart failure, 42% greater risk of developing cardiovascular disease and 22% increased risk of developing stroke. Common heart conditions caused by cancer treatments can include:

• Arrhythmia or abnormal heart rhythm.
• Cardiomyopathy is a condition where the heart pumps less efficiently, which decreases the amount of blood and oxygen sent to the organs and may increase risk for blood clots and heart attacks.
• Congestive heart failure develops when the heart can’t pump enough blood. This can damage your organs and cause fluid to build up in your lungs.
• Coronary artery disease is a narrowing or blocking of coronary arteries usually caused by plaque buildup.
• Hypertension is blood pressure that is too high. When left untreated high blood pressure can lead to heart attack, stroke and other health problems.
• Hypotension or blood pressure that is too low can cause dizziness or lightheadedness, nausea, fainting and other symptoms
• Myocarditis is swelling or inflammation of the heart muscle. This causes an abnormal heartbeat and can weaken the heart muscle. A weakened heart can lead to cardiomyopathy.
• Peripheral vascular disease is narrowing or blocking caused by plaque build-up outside of the coronary arteries.
• Valve disease is caused when heart valves narrow or weaken. This causes abnormal blood flow through the heart’s valves.

Preventing Cardiotoxicity

Preventing cardiotoxicity involves medical strategies to limit exposure, managing risk and lifestyle factors, and carefully monitoring heart health. This is done while trying not to interrupt cancer care.

Limiting Exposure

Reducing the cumulative doses of medications known to cause cardiotoxicity can help reduce the risk of heart damage. Your cardio-oncologist may prescribe a drug like dexrazoxane to help prevent or decrease the thickening of the heart muscle. A thickened heart muscle is a type of cardiomyopathy. Thickening in the heart muscle makes it hard for the heart to pump blood effectively, which can lead to heart failure.

Managing Risk and Lifestyle Factors

You can help reduce your risk by keeping blood pressure under control, lowering your cholesterol, maintaining a healthy blood sugar level, eating a healthy diet, quitting smoking and exercising regularly.

Heart Monitoring

Your cardio-oncologist may recommend to regularly check your heart function. This can be done with echocardiogram, electrocardiogram and sometimes cardiac MRI. Watching enables early identification of changes in how the heart functions. Cardiac monitoring is mostly concerned with left ventricular ejection fraction, or how much blood is pumped out of the heart’s main pumping chamber with each heartbeat. 

There are different factors that go into how your heart will be monitored. Your doctor will look at the type of chemotherapy drug and your risk factors. This information will be used to create a monitoring schedule.

Signs and Symptoms

Cardiotoxicity can develop after cancer treatment has ended, even months or years later. It can happen with and without symptoms. Common symptoms include:

• Abdominal enlargement
• Chest pain
• Dizziness
• Fluid retention in legs
• Heart palpitations
• Heart rhythm changes
• Increased coughing
• Shortness of breath
• Weight gain

Risk Factors

The following factors can increase your risk of developing heart issues following cancer treatment:

• Age — 60 years or older or a young child
• Treated with combination therapy of anthracyclines and chest radiation therapy
• Received high-dose radiation therapy to the chest
• Treated with anthracyclines followed by trastuzumab
• Received anthracyclines or trastuzumab and have a history of smoking, high blood pressure, diabetes, obesity or heart problems
• Treated with high doses of anthracyclines
• Sex – women have increased risk

Diagnosis

Diagnosing Cardiotoxicity

A cardio-oncologist can diagnose heart damage caused by cancer treatment. The doctor will evaluate signs and symptoms, review risk factors and history of heart disease. Diagnostic testing can help determine if you are at risk of developing heart disease from cancer treatment.
 

Cardiac Tests

Electrocardiogram (EKG) – This test records the heart’s electrical signal and can indicate changes in the heartbeat.

Imaging Tests

Echocardiogram (Echo) – This ultrasound of the heart gives a comprehensive evaluation of cardiac structures and blood flows through those structures. When performed at the beginning of cancer treatment and at different times during cancer treatments, this test can evaluate changes that could lead to a change in treatment plan. For example, your cardio-oncologist may prescribe medication to protect the heart.

Lab Tests

Blood tests – These tests measure the levels of different proteins in the blood and the risk of heart disease.

Additional advanced-testing options may be used if necessary.

Causes

Not all cancer treatments damage the heart. Those with the most potential to cause damage include:

• Chemotherapy – certain drugs
• Drugs to prevent cancer recurrence
• Monoclonal antibodies
• Radiation therapy – especially to the chest
• Targeted or molecular therapy

Treating Cardiotoxicity

The cardio-oncologist will review the results of your tests and determine if cardiotoxicity treatment is needed. Very often, cardiovascular function improves once the cancer treatment is done.

A personalized treatment plan will be developed for you. This treatment plan may include medications such as aspirin, statins, beta blockers, ACE inhibitors, diuretics and others. Other treatment strategies can include cardiac rehabilitation, nutrition counseling and other therapies.

The cardio-oncologist will monitor your health and adjust treatment as necessary. The goal is to avoid interrupting your cancer treatment and protect the heart at the same time. If necessary, the cardio-oncologist will work with your oncology team to identify alternative treatments for your specific needs.

Clinical Trials

Clinical trials help determine new treatment options for diseases and conditions. Patients with heart disease and cancer have access to clinical trials and should speak with their doctor to determine what trials may work best for them.