Radiation therapy used in cancer treatment can cause problems in the heart and vascular (circulation) system. This effect is called cardiotoxicity. Cardiotoxicity can develop within days or months after radiation but often develops years later. Cardiotoxicity can reduce the patient’s quality of life and increase the risk of death from cardiac-related causes.
A cardiologist and cancer doctor working together can determine an individual patient’s risk for cardiotoxicity by doing certain tests and imaging before radiation therapy starts. If a patient is at risk, the radiation therapy doctor may limit the amount of radiation dose given during treatment, or aim the radiation beams so that they miss the heart. The goal is to balance the benefits of cancer treatment with the risk of damage to the heart.
How does radiation therapy affect the heart?
Radiation therapy to the chest area often is part of the treatment for Hodgkin lymphoma and cancers of the lung, esophagus, or breast. Cardiotoxicity is a risk when a large volume of heart muscle is exposed to a high dose of radiation. Radiation dose is measured in Grays (Gy), and a heart dose of more than 30 – 35 Gy increases the risk of cardiotoxicity.
Radiation can injure the pericardium (the tissue covering the heart), myocardium (the heart muscle itself), the heart valves, coronary arteries and the heart’s electrical system. Some of the problems that may develop are:
- Pericarditis (inflammation of the tissue surrounding the heart)
- Usually develops 6–12 months after radiation therapy
- May be short-term (acute) or chronic
- Premature coronary artery disease and atherosclerosis
- Usually develops 10–15 years after radiation therapy
- Myocarditis (inflammation of the heart muscle)
- Congestive heart failure (loss of heart pumping ability)
- Heart valve disease
- Heart rhythm changes (arrhythmia)
- Caused by damage to the heart’s electrical system
- Cardiomyopathy (enlarged heart)
Who Is At Risk
Who is at risk for radiation damage to the heart?
- Patients with heart disease risk factors (obesity, cigarette smoking, diabetes, family history)
- Patients with a personal history of heart disease
- Patients who receive radiation therapy plus chemotherapy, endocrine therapy or trastuzumab
- Patients who are treated with radiation to the left-side of the chest
A special group of patients at risk are younger, otherwise healthy patients treated for early-stage breast cancer and Hodgkin lymphoma who are cured of their cancer and live for many years after treatment. These patients now can live long enough to develop heart problems later in life.
As treatment and survival improve for lung cancer and esophagus cancer patients, these patients also may develop heart problems later in life caused by radiation therapy.
New Techniques & Outlook
Has the risk of cardiotoxicity declined with newer radiation therapy techniques?
In recognition of the risk of cardiotoxicity from radiation, newer radiation techniques have been developed that minimize radiation to the heart. These technologies, such as three-dimensional treatment planning with dose-volume histogram, intensity-modulated radiotherapy (IMRT) image-guided radiotherapy (IGRT), and active breathing controlled (ABC) radiotherapy have the potential to reduce the risk of radiation-related heart problems. Long-term studies will evaluate the effects of these newer technologies on the heart.
What is the long term outlook for patients treated with radiation therapy?
As more patients are surviving cancer and living longer, knowledge about the long-term effects of treatment is expanding. It is becoming clear that the longer a patient lives after cancer treatment, the more likely that damage to the heart will develop.
Patients who develop radiation-related cardiotoxicity should be under the care of a cardiologist who understands the relationship between cancer treatment and heart problems. Although cardiotoxicity can be life-threatening, many of these problems can be managed effectively with medication and minimally invasive treatments.
What are the special needs of patients who received radiation to the chest and later require heart surgery?
Each patient who receives radiation therapy may have different prior histories and extent of therapy. Each patient needs to be individually evaluated to determine the effect of prior radiation therapy on their heart, lungs and blood vessels. The surgery needs to be well planned with respect to the possibility of radiation damage to the underlying tissues and organs. Patients should seek a Center of Excellence with experience in performing surgery on patients with prior radiation exposure. Centers with experience and who provide a variety of surgical techniques and approaches can provide the patient with the least amount of trauma and .the best outcome.
The Cardio-Oncology Center is a specialized center involving a multi-disciplinary group of specialists, including cardiologists, oncologists, cardiac surgeons and nurses from the Miller Family Heart, Vascular & Thoracic Institute and the Taussig Cancer Center who provide a comprehensive approach to evaluating, diagnosing and treating cardiotoxicity.
Milind Desai, MD – Medical Director
Douglas Johnston, MD – Surgical Director
Resources & Patient Info
If you need more information, contact us, chat online with a nurse or call the Miller Family Heart, Vascular & Thoracic Institute Resource & Information Nurse at 216.445.9288 or toll-free at 866.289.6911. We would be happy to help you.
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