Cardiotoxicity: Cancer Treatment and Heart Health
Table of Contents
Key takeaways
- Cardiotoxicity means heart dysfunction linked to a medicine, radiotherapy or cancer-treatment pathway.
- It can involve heart muscle weakness, rhythm problems, high blood pressure, clotting, myocarditis, valve disease or coronary artery disease.
- Symptoms such as breathlessness, chest pain, swelling, palpitations, fainting or sudden fatigue during cancer treatment should be reported promptly.
- People at higher risk may need baseline echocardiography, blood tests and ongoing cardio-oncology monitoring before, during and after treatment.
- Never stop cancer treatment or heart medicines without medical advice; decisions should be made by oncology and cardiology teams together.
Overview
Cardiotoxicity describes unwanted effects of cancer treatment on the heart and circulation. It does not mean every cancer treatment damages the heart. Many people complete treatment without major cardiac problems. The aim of cardio-oncology care is to identify risk early, monitor carefully and protect both cancer outcomes and heart health.
Heart effects can happen during treatment, shortly afterwards or years later. Some are reversible when recognised early; others need long-term management. For women treated for breast cancer or chest cancers, the topic is especially relevant because anthracycline chemotherapy, HER2-targeted treatment and radiotherapy near the chest can all require heart-aware planning. The right balance depends on cancer type, stage, treatment benefit, previous heart health and personal priorities.
How cancer treatment can affect the heart
Different treatments affect the cardiovascular system in different ways. Anthracyclines can injure heart muscle cells through oxidative stress, mitochondrial injury and topoisomerase-related DNA damage pathways. HER2-targeted therapies can interfere with signalling that helps heart muscle cells cope with stress. Radiotherapy involving the chest can, over time, contribute to coronary artery disease, valve disease, pericardial disease or heart muscle fibrosis.
Some targeted therapies can raise blood pressure, increase clot risk, affect the QT interval or trigger rhythm problems. Immune checkpoint inhibitors can rarely cause myocarditis, an inflammatory heart condition that can be serious. Hormonal therapies and some supportive medicines can also affect metabolic or clotting risk. Because mechanisms differ, monitoring is matched to the treatment and the person’s baseline risk.
Symptoms
Possible symptoms include breathlessness, reduced exercise tolerance, unusual fatigue, ankle or abdominal swelling, rapid weight gain from fluid, palpitations, dizziness, fainting, chest pain, chest pressure, new high blood pressure, persistent cough when lying down or waking breathless at night. Some people have no symptoms at first, which is why planned monitoring can matter.
Symptoms during cancer treatment can have several causes, including anaemia, infection, lung problems, blood clots, anxiety, medication side effects or progression of cancer. That overlap is exactly why new or worsening symptoms should be reported rather than self-managed.
Risk factors
Risk is higher in people with previous heart failure, cardiomyopathy, coronary artery disease, heart valve disease, high blood pressure, diabetes, kidney disease, obesity, smoking history or previous chest radiotherapy. Risk can also rise with older age, higher cumulative doses of some medicines, combined treatment types, and abnormal baseline heart tests.
Life stage can influence planning. Pregnancy after cardiotoxic treatment, premature menopause after cancer treatment and long survivorship all deserve cardiovascular risk review. A person who had cancer treatment years ago should tell future clinicians about the treatment received, especially if new heart symptoms develop.
Monitoring and diagnosis
Monitoring may include baseline cardiovascular history, blood pressure, ECG, echocardiography, cardiac biomarkers such as troponin or natriuretic peptides, and cardiovascular risk assessment. Echocardiography can measure left ventricular ejection fraction and sometimes global longitudinal strain, which may show early functional change before symptoms appear.
If symptoms develop, further tests may include repeat echocardiography, cardiac MRI, CT coronary imaging, rhythm monitoring, blood tests, chest imaging or assessment for pulmonary embolism. The goal is to decide whether symptoms are treatment-related, cancer-related or due to another condition, and whether cancer treatment can safely continue, pause or change.
Monitoring does not end automatically when cancer treatment finishes. Survivorship plans may include blood pressure checks, cholesterol and diabetes review, repeat heart imaging for higher-risk survivors and advice about future pregnancy or surgery. Keeping a treatment summary helps future clinicians recognise late effects that might otherwise be missed.
Treatment and prevention
Prevention starts with identifying risk before treatment. Oncologists may adjust treatment choice, dose, schedule or radiotherapy planning where clinically appropriate. Cardiologists may optimise blood pressure, cholesterol, diabetes and existing heart disease before therapy begins. Some higher-risk patients may be considered for heart-protective medicines, but this must be individualised.
If cardiotoxicity is suspected, management may involve heart failure medicines, rhythm treatment, blood pressure control, anticoagulation when indicated, temporary interruption or modification of cancer treatment, or closer monitoring. These choices should be shared between oncology and cardiology teams because under-treating cancer and under-treating heart disease both carry risk.
Good communication between teams is central. Patients should know which service to contact for chest symptoms, who reviews heart scans and whether abnormal results change the cancer-treatment plan. This is particularly important when treatment is given across more than one hospital or when private and NHS care overlap.
For immune-related myocarditis, urgent specialist assessment is needed because treatment pathways differ from standard heart failure care and may involve immunosuppression. For radiotherapy-related disease, long-term surveillance may be needed because problems can appear years later.
Practical self-care during cancer treatment
There are no home remedies that prevent cardiotoxicity reliably. Practical self-care means attending monitoring appointments, reporting symptoms early, keeping a list of cancer medicines received, taking heart medicines as prescribed and avoiding smoking. Gentle activity may help maintain function when approved by the care team, but new breathlessness, chest pain, dizziness or fever should pause exercise until advice is obtained.
Nutrition should focus on maintaining strength during treatment while following any oncology dietary advice. People with fluid retention or heart failure may be advised to limit salt or monitor weight. Supplements should be checked with the oncology team because some can interact with cancer treatment or affect bleeding risk.
When to seek medical advice
Tell the oncology team promptly about new breathlessness, swelling, chest discomfort, palpitations, dizziness, fainting, persistent cough when lying flat, sudden weight gain or unusually severe fatigue. Use NHS 111 for urgent advice if symptoms are worrying and the oncology team is not immediately reachable.
Call 999 for severe chest pain, severe breathlessness, collapse, signs of stroke, coughing blood, blue lips, confusion or a very fast irregular heartbeat with faintness.
Sources
- European Society of Cardiology: 2022 cardio-oncology guidelines: academic.oup.com guidance page link unavailable during validation (academic.oup.com guidance page, link unavailable during validation)
Relevance: Provides specialist guideline support for risk assessment, monitoring and management of cancer therapy-related cardiovascular toxicity. - NICE: Suspected cancer recognition and referral: https://www.nice.org.uk/guidance/ng12
Relevance: Supports UK-facing caution around persistent symptoms and cancer care pathways. - NHS: Chemotherapy side effects: https://www.nhs.uk/conditions/chemotherapy/side-effects/
Relevance: Provides patient-facing NHS context on chemotherapy side effects and when to contact the care team. - PubMed Central: Cardio-oncology review: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8037585/
Relevance: Reviews mechanisms, monitoring and management principles for cardiotoxicity across cancer therapies.
Disclaimer
Educational only. Results vary. Not a cure.
Details that must be confirmed before publishing: confirm whether WHM wants a separate breast-cancer-specific cardiotoxicity article, as this topic can support a more targeted companion page.