Cardiotoxicity: Cancer Treatment and the Heart — Plain-English Guide
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick answer
Cardiotoxicity is heart damage caused by certain chemotherapy drugs, targeted therapy drugs or chest radiation, making it harder for the heart to pump blood [1]. Up to 20% of people treated for cancer may develop heart problems. Attend all heart monitoring during and after treatment, and call 911 for severe symptoms such as rapidly worsening chest pain [1].
What the research says
According to PubMed:
Several factors raise the risk of heart damage from anthracycline chemotherapy. A meta-analysis of 13 studies in breast cancer found higher odds of anthracycline-induced cardiotoxicity with trastuzumab use (odds ratio 2.84), higher cumulative anthracycline dose (1.45), hypertension (2.95), diabetes (1.39), coronary heart disease (2.17), and tumor metastasis (1.91). Body mass index showed no clear effect. The authors concluded that high-risk patients need closer cardiac monitoring and protection. (Zhang et al., Front Oncol, 2022 [7]).
Heart imaging during treatment can flag trouble early. A meta-analysis of 21 studies with 1,782 patients treated with anthracyclines, with or without trastuzumab, found that about 21% developed cancer therapy-related cardiac dysfunction (pooled incidence 21.0%, range 9.3%–43.8%). Worse global longitudinal strain on echocardiography during treatment was linked to a much higher risk (odds ratio 12.27). The authors noted publication bias and a need for larger prospective studies. (Oikonomou et al., JAMA Cardiol, 2019 [8]).
Study details are from PubMed abstracts.
What is cardiotoxicity?
Cardiotoxicity is heart damage that arises from certain cancer treatments or drugs [1]. The word simply combines “cardio” (heart) with “toxicity” (damage from a substance). When treatment harms the heart, it can make it harder for your heart to pump blood throughout your body the way it should [1].
In severe cases, cardiotoxicity may lead to cardiomyopathy, a heart muscle condition that makes it even harder for the heart to pump [1]. This is why heart monitoring matters so much during and after cancer treatment.
One important fact shapes everything about this condition: cardiotoxicity sometimes develops years after cancer treatment [1] [3] ends. This is especially true for adults who received cancer treatment during childhood [1]. By the time symptoms appear, the link to a long-past treatment may not be obvious — which is why cancer survivors should tell every healthcare provider about treatments they received, even decades ago.
Cardiotoxicity is not common overall. However, it may be common in people who take certain chemotherapy or targeted therapy drugs [1]. You may also develop heart problems after having radiation therapy to the chest [1].
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 [1].
It is also somewhat common in adults who had cancer treatment as a child. The exact rate of cardiotoxicity in people who had cancer treatment as an adult is difficult to pin down, but some groups estimate that up to 20% of this population may develop heart problems [1], with up to 7% to 10% developing cardiomyopathy or heart failure [1].
Who is affected | Why the risk is higher |
People taking certain chemotherapy drugs (anthracyclines) | |
People taking targeted therapy (trastuzumab) | Most likely to cause cardiomyopathy when combined with an anthracycline [1] |
People who had radiation therapy to the chest | Radiation can damage the heart tissue in the treatment field |
Adults treated for cancer in childhood | Damage can surface years or decades after treatment ends |
Anyone who has had any cancer treatment | Risk is possible with all treatments, though usually low |
How does cardiotoxicity affect my body?
Cardiotoxicity can show up as several different heart problems. The same underlying damage can take different forms depending on how and where the heart was injured.
Possible heart problem | What it means in plain language |
Cardiomyopathy | The heart muscle itself becomes weaker |
Heart attack (myocardial infarction) | Blood flow to part of the heart muscle is cut off |
Coronary artery disease | The arteries that feed the heart become narrowed or blocked |
Heart failure | The heart cannot pump enough blood for the body's needs |
Heart valve disease | The heart's valves do not open or close properly |
Irregular heart rhythms (arrhythmia) | The heartbeat becomes too fast, too slow, or unsteady |
Fluid buildup around the heart | Fluid collects in the space around the heart |
Low or high blood pressure | Blood pressure drops below or rises above healthy levels |
Slow heart rate | The heart beats fewer times per minute than it should |
Thickening of the heart's lining (constrictive pericarditis) [1] | The sac around the heart stiffens and squeezes the heart |
What are the symptoms of cardiotoxicity?
Cardiotoxicity can cause chest pain, dizziness, heart palpitations, shortness of breath, belly swelling and leg swelling [1], symptoms that are easy to miss.
Abdomen enlargement (abdominal distension) — the belly swells from fluid
Chest pain
Dizziness
Heart palpitations — feeling your heart pound, flutter, or race
Shortness of breath (dyspnea)
Swelling and fluid retention (edema) in the legs [1]
These symptoms can be easy to miss or to blame on other things — fatigue from treatment, for example. That is one reason the symptom list deserves attention, especially in the months and years after cancer treatment ends.
What causes cardiotoxicity?
Cardiotoxicity is caused by certain cancer treatments, mainly anthracycline chemotherapy, the targeted drug trastuzumab and radiation therapy to the chest [1]. The three main causes are:
Anthracyclines. These are chemotherapy medications, such as doxorubicin (Adriamycin) [1] [3], often used to treat leukemia, lymphoma, breast cancer, sarcoma, or multiple myeloma [1].
Trastuzumab (Herceptin). This is a targeted therapy drug commonly used to treat breast cancer, stomach cancer, or cancer of the gastroesophageal junction — the spot where your food pipe (esophagus) connects to your stomach [1] [4]. Trastuzumab is most likely to cause cardiomyopathy if it is combined with an anthracycline medication [1].
Radiation therapy to the chest. This is often used to treat breast cancer, lymphoma or lung cancer [1].
Cause | Drug or treatment type | Cancers it commonly treats | Extra risk note |
Anthracyclines (e.g., doxorubicin/Adriamycin) | Chemotherapy | Leukemia, lymphoma, breast cancer, sarcoma, multiple myeloma | Often not reversible; needs long-term treatment |
Trastuzumab (Herceptin) | Targeted therapy | Breast cancer, stomach cancer, gastroesophageal junction cancer | Most likely to cause cardiomyopathy when combined with an anthracycline |
Chest radiation therapy | Radiation | Breast cancer, lymphoma, lung cancer | Very difficult to reverse; may require long-term treatment or surgery |
How is cardiotoxicity diagnosed?
Healthcare providers diagnose cardiotoxicity by measuring the pumping function of your heart using left ventricular ejection fraction (LVEF) and by evaluating the function of your heart valves [1]. LVEF measures how much blood pumps out of your lower left heart chamber — the left ventricle — each time your heart contracts [1].
Providers use several tests to measure the heart's pumping function and valve function:
Test | How it works |
Echocardiogram | The most common imaging tool in cardiotoxicity diagnosis; uses electrodes and ultrasound to check your heartbeat and view blood flow through your heart [1] |
Cardiac MRI | Some experts consider it the gold standard for detecting cardiotoxicity; uses magnets, radio waves, and a special computer to create detailed images of the heart's structures [1] |
Cardiac stress test | Measures how your heart responds to intense activity; you walk on a treadmill or ride a stationary bike while a machine measures heart rate and blood pressure [1] |
MUGA scan (multigated acquisition scan) | Evaluates the function of the heart's ventricles using a safe radioactive tracer; your provider calculates your ejection fraction from how the tracer moves through your bloodstream [1] |
Cardiac CT scan | Many X-rays from multiple angles create a detailed picture of your heart; may be most useful for people with suspected cardiotoxicity after chest radiation therapy [1] |
How is cardiotoxicity treated?
Your healthcare provider may recommend stopping certain medicines or decreasing their doses, depending on your current medication regimen [1]. Your provider may also prescribe medications to help your heart work more efficiently:
Medication | Example drugs | How it helps |
ACE inhibitors | Lisinopril (Zestril), fosinopril sodium (Monopril) | Opens your arteries and improves blood flow [1] |
Beta-blockers | Metoprolol (Lopressor), atenolol (Tenormin) | Increases blood flow and slows your heart rate [1] |
Digoxin (digitalis) | Lanoxin | Slows your heart rate and helps it beat more efficiently [1] |
Diuretics | Furosemide (Lasix) | Rids your body of excess fluid [1] |
Vasodilators | Isosorbide dinitrate (Isordil) | Opens up (dilates) your blood vessels so blood flows more efficiently [1] |
Can cardiotoxicity be reversed?
Cardiotoxicity may be reversible — but it depends on what caused it.
Research has shown that cardiotoxicity that arises after using trastuzumab may be reversible [1]. Cardiotoxicity that arises from anthracycline use is often not reversible and requires long-term treatment [1]. Cardiotoxicity related to chest radiation is also very difficult to reverse and may require long-term treatment, possibly even surgery [1].
Cause | Can it be reversed? |
Trastuzumab (Herceptin) | Research shows it may be reversible |
Anthracyclines (e.g., doxorubicin) | Often not reversible; requires long-term treatment |
Chest radiation therapy | Very difficult to reverse; may require long-term treatment, possibly surgery |
Can cardiotoxicity be prevented?
Cardiotoxicity cannot always be prevented, but your care team can lower the risk, for example by limiting anthracycline doses and controlling blood pressure and diabetes, and regular heart imaging during cancer treatment may help catch it early, when it is more likely to be treated successfully [1]. It is important to discuss the potential health risks and benefits of treatments with your provider if you have 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 [1] [2].
When should I get emergency help?
Emergency: 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, or weight gain of more than 3 pounds in one week [1].
These are warning signs that your heart may be struggling — not something to monitor at home.
What's the bottom line?
Cardiotoxicity is a reminder that cancer treatments, for all their life-saving power, can be hard on the heart. The damage may show up right away or years later. Some types are reversible; others require long-term treatment, sometimes surgery. The practical takeaways: know which of your treatments carry heart risk, keep every heart-monitoring appointment during and after treatment, and act quickly on the warning signs. And if you are a cancer survivor — whether treatment ended last year or thirty years ago — let every healthcare provider know your history. Talking with your provider about the benefits and potential risks of any cancer treatment remains the best protection you have.
Looking for plain-English guides on heart health and cancer care? Explore more at Rinnit.com.
Frequently asked questions
What is cardiotoxicity?
Cardiotoxicity is heart damage that arises from certain cancer treatments or drugs, making it harder for your heart to pump blood throughout your body.
Which cancer treatments cause cardiotoxicity?
The main causes are anthracycline chemotherapy drugs (such as doxorubicin/Adriamycin), the targeted therapy trastuzumab (Herceptin), and radiation therapy to the chest.
How common is cardiotoxicity?
It is not common overall but may be common with certain chemotherapy or targeted therapy drugs. Some groups estimate up to 20% of people treated for cancer may develop heart problems, with up to 7% to 10% developing cardiomyopathy or heart failure.
Can cardiotoxicity develop years after treatment?
Yes. It sometimes develops years after cancer treatment, especially in adults who received cancer treatment during childhood.
What is cardiomyopathy?
Cardiomyopathy is a heart muscle condition that makes it harder for your heart to pump blood; severe cardiotoxicity may lead to it.
What are the symptoms of cardiotoxicity?
Abdomen enlargement, chest pain, dizziness, heart palpitations, shortness of breath (dyspnea), and swelling and fluid retention (edema) in the legs.
What heart problems can cardiotoxicity cause?
It may cause cardiomyopathy, heart attacks, 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, and thickening of the heart's lining (constrictive pericarditis).
How is cardiotoxicity diagnosed?
Providers measure the heart's pumping function using left ventricular ejection fraction (LVEF) and evaluate heart valve function, using tests like an echocardiogram, cardiac MRI, cardiac stress test, MUGA scan, or cardiac CT scan.
What is LVEF?
LVEF (left ventricular ejection fraction) measures how much blood pumps out of your lower left heart chamber (the left ventricle) each time your heart contracts.
What is the most common test for cardiotoxicity?
The echocardiogram, which uses electrodes and ultrasound to check your heartbeat and view blood flow through your heart. Some experts consider cardiac MRI the gold standard for detecting cardiotoxicity.
How is cardiotoxicity treated?
Your provider may stop or reduce certain medicines and prescribe drugs that help your heart work more efficiently — ACE inhibitors, beta-blockers, digoxin, diuretics, or vasodilators.
Can cardiotoxicity be reversed?
Sometimes. Cardiotoxicity from trastuzumab may be reversible; damage from anthracyclines is often not reversible and needs long-term treatment; damage from chest radiation is very difficult to reverse and may require long-term treatment or surgery.
Can I prevent cardiotoxicity?
It cannot always be prevented, but your care team can lower the risk, for example by limiting anthracycline doses and controlling blood pressure and diabetes. You can improve your chances of catching it early with regular heart imaging during cancer treatment, and by discussing treatment risks and benefits with your provider.
When should I call 911?
Call 911 and go to your nearest emergency center for persistent or racing heart palpitations, dizziness or passing out, rapidly worsening shortness of breath or chest pain, swelling of your throat or lips, unusual leg or foot swelling, or weight gain of more than 3 pounds in one week.
Is doxorubicin the same as Adriamycin?
Yes — doxorubicin (Adriamycin) is an anthracycline chemotherapy drug often used to treat leukemia, lymphoma, breast cancer, sarcoma, or multiple myeloma, and it carries a known risk of heart damage.
Related reading
Echocardiogram With Strain: How Strain Imaging Spots Early Heart Damage explains the strain echo that spots early heart muscle changes.
This article is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Never stop or change cancer treatment without talking to your oncology team. Always seek the advice of your physician or qualified health provider with any questions you may have regarding a medical condition. If you think you may have a medical emergency, call your doctor or 911 immediately.
References
Cleveland Clinic. Cardiotoxicity: Cancer Treatment and the Heart. Cleveland Clinic. Last updated June 20, 2022. https://my.clevelandclinic.org/health/diseases/16858-chemotherapy--the-heart-cardiotoxicity
Awadalla M, et al. Advanced imaging modalities to detect cardiotoxicity. Curr Probl Cancer. 2018;42(4):386-396. PMID 30297038. https://doi.org/10.1016/j.currproblcancer.2018.05.005
Cancer Research UK. Doxorubicin. Cancer Research UK. Last reviewed November 21, 2023. https://www.cancerresearchuk.org/about-cancer/treatment/drugs/doxorubicin
Cancer Research UK. Trastuzumab. Cancer Research UK. Last reviewed March 18, 2024. https://www.cancerresearchuk.org/about-cancer/treatment/drugs/trastuzumab
Chatterjee K, et al. Doxorubicin cardiomyopathy. Cardiology. 2010;115(2):155-162. PMID 20016174. https://doi.org/10.1159/000265166
Montisci A, et al. Severe cardiac toxicity induced by cancer therapies requiring intensive care unit admission. Front Cardiovasc Med. 2021;8:713694. PMID 34540917. https://doi.org/10.3389/fcvm.2021.713694
Zhang M, Yang H, Xu C, et al. Risk factors for anthracycline-induced cardiotoxicity in breast cancer treatment: a meta-analysis. Front Oncol. 2022;12:899782. PMID 35785172. https://doi.org/10.3389/fonc.2022.899782
Oikonomou EK, Kokkinidis DG, Kampaktsis PN, et al. Assessment of prognostic value of left ventricular global longitudinal strain for early prediction of chemotherapy-induced cardiotoxicity: a systematic review and meta-analysis. JAMA Cardiol. 2019;4(10):1007-1018. PMID 31433450. https://doi.org/10.1001/jamacardio.2019.2952
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