How we protect breast cancer patients’ hearts during radiation therapy

Many breast cancer patients undergo radiation therapy as part of their treatment. While radiation therapy often comes with side effects, such as skin irritation and fatigue, patients with left-sided breast cancer have an added concern: potential for heart disease.

Years ago, researchers discovered that many patients who underwent radiation therapy to the left breast later developed heart conditions, including pericardial disease, conduction abnormalities, coronary artery disease, congestive heart disease, heart valve disease and even sudden cardiac death. Scientists linked these problems to the heart’s exposure to radiation during treatment. That’s why MD Anderson now takes extra precautions to protect patients’ hearts during radiation therapy. Our goal is to offer state-of-the-art radiation therapy for breast cancer without increasing the risk of long-term heart issues.

How we protect the heart during radiation therapy

Here are four methods that we use at MD Anderson to reduce the risk of radiation-induced heart disease.

Multi-leaf collimation: Our linear accelerator machines are equipped with a special shield to protect the heart from radiation exposure. This shield has multiple leafs that can move independently in and out of the path of the radiation beam to allow the radiation to target cancer cells while protecting nearby healthy tissue.

Prone technique: We sometimes use this method for large-chested patients who are able to lay face-down and suspend their breast away from the chest. This allows us to radiate the tumor and protect the chest wall simultaneously.

Respiratory-gating: Also known as deep inspiration breath-hold (DIBH) technique, respiratory-gating requires patients to hold their breath while radiation therapy is delivered. Doing so allows the heart to temporarily move closer to the patient’s back and further away from the treatment field. This minimizes radiation exposure to both the lung and heart. To ensure patient safety, the machine automatically shuts off when the patient can no longer hold her breath. Although it might sound difficult, most patients are able to hold their breath while the radiation is delivered with just a little coaching. 

We’ve successfully treated a large number of left-sided breast cancer cases using this technique. We also use this method occasionally to treat right-sided breast cancer patients who have a smaller lung volume or have a heart that’s more centrally located. 

Forward-planned and inverse-planned intensity-modulated radiation therapy: Intensity-modulated radiation therapy (IMRT) uses advanced software to deliver a precise dose of radiation, based on the area of tumor, size, volume to be treated, and accounting for the exact shape, location and normal tissues.

With IMRT, our radiation oncologists can adjust the intensity of radiation beams across the treatment area as needed with precision accuracy. This means we can deliver higher radiation doses than traditional radiation therapy methods, while reducing exposure to healthy tissues.

How we determine the best method for you

The technique we use to treat a patient is ultimately based on that individual’s anatomy. Before the start of treatment, each patient undergoes a simulation so that we can identify the best method for her. During simulation, we evaluate whether the prone technique is an option. If it’s not, then we perform a deep inspiration and free breathing scan on our patients, and our dosimetrists and radiation physicists help us evaluate the heart’s position with respect to the treatment fields. If we’re not able to meet the normal tissue radiation dose constraints, which are based on studies for the heart and lung, then we choose an IMRT treatment plan.

While identifying the best plan can take time in patients with difficult anatomy, remember that it’s worth the wait for us to be able to personalize treatment to minimize the impact of radiation on your body.  

Focus on a healthy lifestyle

The precautions we take during radiation therapy play an important part in protecting breast cancer patients from heart disease, but they’re not the only factor in reducing your risk. Keeping your heart healthy through regular physical activity is also important. And, MD Anderson has a program that can help with this – our Healthy Heart Program, which was developed to help patients improve their overall fitness and heart health. Participants receive a personalized exercise routine, as well as information on their personal risk of heart disease and strategies to improve their heart health. If you’re interested in participating in the Healthy Heart Program, ask your MD Anderson doctor for a referral.

Pamela J. Schlembach, M.D., is a radiation oncologist at MD Anderson in The Woodlands.

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