Some cancer treatments can affect how your heart works. This may cause heart problems that are either short term or long-term.
Chemotherapy uses anti-cancer (cytotoxic) drugs to destroy cancer cells. Some types of chemotherapy may cause heart problems. The risk can be higher if you are:
- taking several chemotherapy drugs together
- having chemotherapy with chest radiotherapy
- also having some types of targeted therapies.
Your age when you have chemotherapy may also increase the risk of heart problems. With some types of chemotherapy the risk of a heart problem is increased in:
- young children
- people over 65 years old.
Your cancer doctor will explain any risks before you start chemotherapy. Different drugs can cause different problems:
- Some drugs are only likely to cause heart problems if you have a high dose. Your cancer doctor will plan your treatment carefully and record the doses you are given.
- Some drugs may cause heart changes during or shortly after you have treatment.
- Some drugs can cause heart problems many years later – these are known as late effects.
Some chemotherapy drugs are given into a vein (intravenously) with large amounts of fluid. If you already have a heart condition, this can put pressure on your heart and may cause problems. Your nurse will monitor you for any signs of problems while you have these treatments.
Heart tests and chemotherapy
Before treatment, you may have blood tests and a scan to monitor how your heart is working. For some types of chemotherapy, you will have these tests again during and after your treatment. These tests look for early signs of heart muscle damage and monitor your heart function. You may not have any symptoms, but it is important to treat early signs to stop further damage.
Heart symptoms during chemotherapy
Sometimes chemotherapy causes symptoms that need urgent treatment to prevent serious problems. You should tell your doctor or nurse straight away if you:
- have chest tightness, pain or discomfort
- have pain that spreads to your shoulders, neck, back, jaw or arms
- feel unwell, sick or sweaty
- have shortness of breath or are wheezing
- black out (faint)
- feel dizzy or light-headed can feel your heart beating (palpitations).
If you get any of these symptoms during treatment, your doctors will stop the chemotherapy drug and check your heart. They may change the type of chemotherapy to one that does not cause heart problems.
Anthracyclines are a group of chemotherapy drugs that most commonly affect the heart. They are used to treat many different types of cancer.
This type of chemotherapy includes the drugs:
Many people who have these drugs do not develop any heart problems. But sometimes they can cause heart muscle damage. This can cause symptoms during, shortly after or years after treatment (late effects).
To help reduce the risk of heart problems, doxorubicin can be wrapped in a fatty covering called a liposome. The liposome helps prevent the drug from reaching areas with small blood vessels, such as the heart. This treatment is called liposomal doxorubicin (Caelyx®, Myocet®). Your cancer doctor can tell you if it is suitable for you.
Other chemotherapy drugs
Sometimes other types of chemotherapy drugs can affect the heart. A small number of people may develop heart problems. These may develop within hours or up to a few days after having these treatments.
Alkylating agents are used to treat many different types of cancer. Commonly used alkylating agents include:
These are used to treat different types of cancer including ovary, breast, prostate and lung cancer. The 2 main taxanes are:
These chemotherapy drugs are used to treat different cancers, such as bowel and breast cancer. Commonly used fluoropyrimidines include:
Other chemotherapy drugs
Other commonly used chemotherapy drugs can also affect the heart. But the risk of heart problems with these drugs issmall. They include:
Different drugs can cause different heart problems. Some may cause high blood pressure or abnormal heart rhythms. Others can cause symptoms of angina or heart failure. Researchers are still looking at the effect some newer drugs have on heart health.
Heart tests and treatment
Before treatment, you may have blood tests and scans to monitor how your heart is working. For some types of drug, you will have these tests again during and after your treatment. This is done to look for early signs of heart muscle damage.
You may not have any symptoms, but it is important to monitor your heart. This is so that any early signs can be treated to stop further damage.
There are many different targeted and immunotherapy drugs. Below are examples of the different types of drugs that may affect the heart. Your cancer doctor, specialist nurse or pharmacist will talk to you about the drug you are having. They will explain any risks before you start treatment.
Cancer growth inhibitors
Chemical signals tell cells in the body how and when to develop and divide. Cancer growth inhibitors are treatments that make it difficult for cancer cells to receive these signals.
Cancer growth inhibitors that can affect the heart include:
Tumours need a blood supply to be able to survive. Without a good blood supply, the tumour does not get the oxygen and nutrients it needs. This may slow the tumour’s growth or sometimes shrink it. Angiogenesis inhibitors block the chemical signals cells use to make blood vessels grow. This makes it difficult for a tumour to develop the network of blood vessels it needs to get a blood supply.
Angiogenesis inhibitors that can affect the heart include:
Checkpoint inhibitors affect a type of white blood cell called a lymphocyte. Lymphocytes are an important part of the immune system. When they are active, they can attack another cell such as a cancer cell. Checkpoint inhibitors block the signals that ‘switch off’ lymphocytes. This means the lymphocyte stays active and is able to attack the cancer cells. Some checkpoint inhibitors can cause inflammation of the heart (myocarditis) and arrhythmias.
Checkpoint inhibitors that can affect the heart include:
Proteasome inhibitors interfere with enzymes (proteasomes) that are found in all cells, including cancer cells. This may cause the cancer cells to die and can stop them from growing.
Proteasome inhibitors that can affect heart function include:
Immune system modulators
Immune system modulators help the immune system work better.
Examples that may affect the heart function include:
Radiotherapy uses high-energy rays, such as x-rays, to treat cancer. Most people who have radiotherapy do not develop heart problems after treatment.
Radiotherapy is only likely to cause heart problems if the heart is in the area being treated. For example, this could be if you have radiotherapy for breast cancer in the left breast. If you have radiotherapy to another part of your body, away from the heart, it is unlikely to damage the heart.
Radiotherapy techniques are very accurate. Treatment can usually be planned to avoid affecting the heart. This means heart problems after radiotherapy have become rare.
Radiotherapy to the heart can:
- affect the coronary arteries, which can lead to coronary heart disease
- cause inflammation of the layers that cover of the heart (pericarditis)
- cause a build-up of fluid between the layers that cover the heart (pericardial effusion)
- damage the heart muscle
- damage the heart valves
- affect the heart’s electrical system and cause an abnormal rhythm.
The risk of damage to the heart depends on:
- the total dose of radiotherapy given
- how much of the heart is in the treatment area.
The higher the overall dose of radiotherapy and the amount of the heart exposed, the greater the risk of damage. But the risk is still very small.
The risk of heart damage is also increased if:
- you are having chemotherapy at the same time
- you already have a heart condition.
Heart problems can sometimes happen during treatment. Or they may develop months or years later (late effects).
If you were told the radiotherapy may affect your heart, you can reduce the risk by making healthy lifestyle choices.,
Your GP may arrange regular appointments after cancer treatment to check for signs of heart problems. At the appointments, you may have heart tests such as:
- your blood pressure checked
- a blood test to check your cholesterol levels
- scans to check how your heart is working.
Heart symptoms after radiotherapy
If you have any warning signs of heart problems, it is important to let your doctor know straight away.
Early treatment for a heart problem can prevent further problems.
Sometimes the symptoms of heart problems are like the symptoms of other conditions. But it is important to get any new symptom checked by your doctor. Always tell your doctor if you:
- have chest discomfort, pain or tightness
- have pain that spreads to your arm, neck, jaw, stomach or back
- feel short of breath
- feel unusually tired or weak (fatigue)
- have swelling in your feet, ankles, tummy or lower back
- have palpitations, which might feel like a thumping or fluttering in your chest have blackouts (fainting)
- feel dizzy or light-headed.
A heart attack is life-threatening. If you think you or someone else is having a heart attack, phone 999 for an ambulance straight away.
Hormonal therapy drugs are often used to treat breast cancer or prostate cancer. Sometimes they are used to treat other types of cancer.
Hormonal therapies do not usually damage the heart directly, but they can affect your risk factors for heart problems. They may raise your blood pressure or cholesterol levels.
People also tend to gain weight while taking hormonal therapies. This can increase your risk of developing diabetes and heart problems in the future. Women taking hormonal therapies may have an early menopause. The risk of heart problems increases in women after the menopause.
Reducing the risk of heart problems
If you are taking a hormonal therapy, you can reduce these risks by making healthy lifestyle changes. Your doctor may also suggest treatments for high blood pressure or high cholesterol.
Surgery is one of the main treatments for cancer. Sometimes surgery can put the heart under stress and cause heart problems. Having drugs to keep you asleep during surgery (general anaesthetic) may also cause heart problems for some people.
If you have a healthy heart, surgery is not usually a problem. But there may be a higher risk of damage to the heart for people who:
- had heart problems before surgery
- have diabetes
- are over 70 years old
- have high blood pressure
- are overweight.
If you have minor surgery and only need to be asleep (anaesthetised) for a short time, the risk may be small. If you have major surgery and need to be asleep for several hours, the risk can be greater.
Your doctor will talk to you about the possible risks of your surgery. Before you have a general anaesthetic, you will have some tests. These are to check your heart and make sure you are fit enough for surgery. If you have a high risk of serious heart problems, your doctors may suggest other cancer treatments you can have.