Spotlight on: Radiation and the Heart
Radiation Treats Cancer Yet May Also Impact Heart Health
Cancer treatments are designed to target cancer cells, but often they take a toll on the rest of the body as well. For some patients undergoing radiation therapy, the condition of the heart may be compromised. At UVA’s new Emily Couric Clinical Cancer Center, advances are being made to lessen the effects of radiation on the heart, while still effectively treating the cancer. UVA radiation oncologist Paul Read, MD, PhD, shares his insight on this important topic.
Q. How can radiation treatment damage the heart?
The most common risk of heart injury from radiation occurs in patients who have breast cancer on the left side. Although very little heart muscle may be irradiated during treatment, an important artery—known as the left anterior descending (LAD) artery that runs down the front part of the heart—may be in the path of radiation beams. This exposure can result in accelerated atherosclerosis (hardening of the arteries) or coronary artery disease (narrowing of the small vessels to the heart), which may appear 15-20 years after treatment.
If a large volume of the heart is irradiated (to doses of 40 Gy or higher), the sack covering the heart called the pericardium can become fibrotic (restrictive pericarditis) or filled with fluid (radiation inflammatory pericarditis), or the heart muscle itself can become weakened (radiation myocarditis), resulting in congestive heart failure.
Fortunately, large volumes of the heart are rarely irradiated, but sometimes this can happen when treating patients who have large, left-sided lung cancers or mesotheliomas. These effects can occur six months to several years after radiation treatment.
Q. What symptoms should cancer patients be aware of to spot a developing problem with their heart?
They should be aware of the symptoms of congestive heart failure (shortness of breath, swelling of the feet) or coronary artery disease (angina, chest pressure, shortness of breath, sweating, left arm or jaw pain, fatigue).
Q. How is UVA working to protect the heart during
When we treat cancer patients with radiation, we do everything possible to avoid treating the heart by using sophisticated delivery techniques. We have several of the most advanced radiation systems in the world. Our radiation oncology team, including Krishni Wijesooriya, PhD, and Monica Morris, MD, is working on groundbreaking techniques to reduce radiation to the heart when treating left-sided breast cancer patients.
We use a treatment technique known as Deep Inhalation Breath Hold. We’ve presented our methods and results for using this treatment at several national meetings. The basic idea is to treat left-sided breast cancer patients while they take a deep breath. This separates the breast or chest wall from the heart so that the heart and LAD artery are not in the path of radiation beams.
Modern radiation delivery units that can deliver the radiation quickly are required. Special CT scans during the planning phase capture images when the patient takes a deep breath. We measure the patient’s breathing and show the patient how deep they are breathing using special biofeedback goggles. This way, patients know at what depth they should hold their breath for each daily treatment. All of this makes the treatment process extremely precise.