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Heart problems can develop after some types of cancer treatment. Heart problems can develop within the first year of treatment or years after treatment is finished. Sometimes heart problems happen as a late effect of treatments for cancer during childhood.
How the heart works
The heart is part of the circulatory system. It is a muscular organ that pumps blood, which contains oxygen and nutrients, throughout the body. A thin membrane (called the pericardium) surrounds the heart, protecting it and anchoring it in the chest.
The heart has 4 chambers. The upper chambers are called atria (each one is called an atrium). The lower chambers are called ventricles. Valves direct the flow of blood through the chambers and into the blood vessels. Nerves control the rhythm and rate of heart beats, or contractions, by sending electrical signals to different parts of the heart.
Treatments for cancer, including certain types of chemotherapy and radiation therapy, can cause heart problems.
Heart problems are most often linked to the total dose given of a chemotherapy drug or being treated with combinations of chemotherapy drugs. Heart damage can occur even with lower doses of drugs if radiation therapy to the chest was previously given.
Chemotherapy drugs that can cause heart damage include:
- anthracycline drugs such as doxorubicin (Adriamycin), daunorubicin (Cerubidine, daunomycin) and epirubicin (Pharmorubicin)
- carboplatin (Paraplatin, Paraplatin AQ)
- paclitaxel (Taxol)
- cyclophosphamide (Procytox)
Radiation therapy to the chest, abdomen or spine or total body irradiation, which may be given before a stem cell transplant, can lead to heart problems. It depends on the total dose of radiation to the chest and amount of heart tissue in the radiation treatment field.
Heart problems linked to radiation therapy are less common than in the past because of changes in treatment methods and doses of radiation.
The young and the elderly are at a greater risk for developing heart problems, with those at a younger age at the time of treatment having the greatest risk.
People with a history of heart disease are at a greater risk of developing heart problems caused by cancer treatment.
Treatments with other medicines may affect the heart and increase the risk of heart problems.
Other factors that can increase the risk of heart problems from chemotherapy or radiation therapy include:
- high blood pressure
- a family history of heart problems, high blood pressure or diabetes
- an inactive lifestyle
- eating a diet high in fat
- early menopause
Types of heart problems
Chemotherapy and radiation therapy may cause problems with how well the heart works and abnormal heart rhythms (arrhythmias). Types of heart problems that can develop include:
- cardiomyopathy and congestive heart failure, which damage and weaken the heart and how well it can pump blood
- a damaged heart valve, which causes the valve to narrow or leak
- coronary artery disease (hardening or narrowing of the heart arteries)
- pericarditis (inflammation of the pericardium)
- pericardial fibrosis (thickening or scarring of the pericardium)
- pericardial effusion (an abnormal buildup of fluid in the pericardium)
- carotid artery disease (hardening or narrowing of the arteries in the neck)
Symptoms of heart problems can vary depending on the type of problem. Mild to moderate heart problems may not cause any symptoms. The problem may only be identified by diagnostic tests.
Symptoms of heart problems include:
- shortness of breath
- dizziness or feeling light-headed
- severe fatigue that prevents exercise or normal play
- chest pain that feels like a heavy pressure or fullness and travels to the arm, chin or face
- sweating, nausea or shortness of breath with chest pain
- sharp pain in the centre or left side of the chest (often worsens when taking a deep breath)
- periods of heart racing or throbbing, or feeling like it is skipping beats
- poor appetite
- swelling in the feet, ankles or abdomen
- cough and wheezing that don’t go away
If symptoms get worse or don’t go away, report them to your doctor or healthcare team without waiting for your next scheduled appointment.
Before treatment for cancer begins, the healthcare team may do tests to check your heart. Tests are repeated during and after treatment to look for any changes. These tests may include:
- an electrocardiogram (ECG) to check heart rate and rhythm
- an echocardiogram (echo, or heart ultrasound) to check the muscle of the heart and how it pumps blood
- a multigated acquisition (MUGA) scan to check the motion of the heart and how well it pumps blood to the body
- blood tests to measure chemicals such as electrolytes
- a stress test to show how your heart works during exercise when it is beating faster
Find out more about tests and procedures.
Preventing heart problems
To prevent heart damage, the healthcare team carefully monitors people who are at risk. They use tests to monitor and check your heart when you have cancer treatments that may damage the heart. If doctors think the heart might be damaged, they may lower the dose of the drug or radiation or stop the treatment entirely to prevent further damage.
Sometimes a drug, such as dexrazoxane (Zinecard), is given before chemotherapy to protect the heart.
As you get older, the risk of certain types of heart disease (such as a heart attack and hardening of the arteries) increases. Factors that may increase the risk of heart problems include smoking, drug use, eating a high-fat diet, not exercising and not having a healthy body weight. Medical conditions that increase the risk of heart disease include diabetes, high blood pressure and high blood cholesterol.
You can help lower your risk of heart problems by:
- not smoking or quitting smoking
- getting to and staying at a healthy body weight
- eating a healthy diet and limiting dietary fat
- exercising moderately on a regular basis
Managing heart problems
If you had cancer treatments that can cause heart damage, a cardiologist may be consulted for more evaluation and treatment.
Some heart problems are treated with medicines. If a heart valve is damaged during treatment, surgery may be needed to replace it. Coronary artery disease may eventually require surgery (angioplasty or a bypass) to treat it. Oxygen therapy may be given for severe shortness of breath.
Life after treatment
If treatment such as chemotherapy or radiation therapy to the chest causes heart damage, you will have to take steps to protect your heart for the rest of your life.
- Aerobic exercise is generally safe and beneficial for the heart. But some types of exercise are particularly stressful to the heart. Check with your healthcare team before playing sports or beginning any exercise program.
- Some conditions, such as pregnancy or an illness with a high fever, can put added stress on the heart. Some drugs (such as cocaine, diet pills, ephedrine and performance-enhancing drugs) can increase stress on the heart and worsen how the heart works.
- If a heart valve is damaged, an antibiotic may be given before having any dental work or other invasive medical procedure. This is to prevent a serious infection of the heart (endocarditis) that can happen if bacteria enters the bloodstream while the work is being done.
All people who are treated for cancer need regular follow-up. The healthcare team will develop a follow-up plan based on the type of cancer, how it was treated and your needs.
Follow-up may include a physical exam and one or more of the following heart function tests:
- a multigated acquisition (MUGA) scan
- an echocardiogram (echo)
- an electrocardiogram (ECG)
I’m extremely grateful to the Canadian Cancer Society for funding my research with an Innovation Grant.
What’s the lifetime risk of getting cancer?
The latest Canadian Cancer Statistics report shows about half of Canadians are expected to be diagnosed with cancer in their lifetime.