Photo: Moffitt Cancer Center
Photo: UF Health
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Economic Backbone: Breast Cancer
Collateral Damage
Breast cancer treatment can take a toll on the heart. Florida clinicians and researchers are focused on ways to mitigate the threat.
Advances in chemotherapy and radiation treatment have helped millions of patients survive breast cancer. But that often comes with a cost of severe heart damage. In a 2022 study published by the National Institutes of Health, 40,800 breast cancer survivors — nearly 8% of all survivors tracked between 1975 and 2016 — died of heart disease.
New studies and approaches offer the promise of reducing or even eliminating that collateral damage.
Patients are benefitting from year-old guidelines from the European Society of Cardiology. The guidelines are “a major development,” says Mohammed Alomar, a University of South Florida medical school faculty member and cardio-oncology program director at the Moffitt Cancer Center in Tampa, because they offer practitioners a variety of treatment strategies based on a centralized repository of research.
They also help to fill a knowledge gap. Cardiologists may not know much about cancer treatment, Alomar says, and oncologists may know little about the heart. The guidelines bridge that divide and help doctors develop mitigation strategies, including diet and exercise regimens, to reduce the cardiac threat.
In a way, heart disease among breast cancer survivors is “a good problem to have,” Alomar says. “Maybe 20 years ago or so, people who ended up with breast cancer with metastases didn’t live long enough to get heart disease.”
Researchers in the state are focused on ways to get ahead of heart complications. University of Florida biomedical engineer Walter O’Dell believes MRIs can detect declines in heart function earlier and more accurately. Most heart imaging relies on ultrasounds. They’re effective, he says, but somewhat limited in the angle doctors can see. In a study funded by the Florida Breast Cancer Foundation, O’Dell found that MRIs can identify trouble brewing before the loss of heart function is noticeable.
The challenge is that ultrasounds are readily available compared with MRIs and don’t take as long to use.
O’Dell and his colleagues are trying to determine whether heart damage can be minimized, or even eliminated, by using protons to deliver radiation to a breast cancer tumor, rather than traditional targeted X-ray delivery. Patients whose cancers are on their left sides are at greater risk for heart damage due to the left ventricle’s proximity.
For those patients, proton delivery may be safer. While an X-ray shoots radiation through the tumor and potentially into the heart, a proton acts more like a battering ram, and there is no “exit dose” that sends radiation into the heart.
In a small-scale study of 10 patients, those who received proton treatment suffered less heart damage and registered a better “ejection fraction,” meaning the heart is pumping out more blood.
“We didn’t expect to see an improvement,” O’Dell says. But one theory is that the proton patient not only did not suffer heart damage but also was able to begin healing sooner than X-ray radiation patients.
It will take years to identify more patients and monitor their post-cancer heart health.
Resource Centers
The European Society of Cardiology Council of Cardio-Oncology focuses on cancer therapy-related cardiovascular diseases. The International Cardio-Oncology Society, the U.S. counterpart, is based in Tampa.
