Subtle, Persistent Changes in Subgroup Receiving More Radiation
According to Dr. Mousseaux, technological advances in breast radiation have significantly reduced by more than half the cardiac doses commonly used 20 years ago. Yet this study, the largest of its kind, confirms earlier research findings that even the smallest radiation doses can cause functional changes in the heart.
Of note, 23 participants exhibited a persistent decrease in LV GLS, all of whom received higher mean radiation doses to the whole heart (2.09 Gy vs. 1.36 Gy) and left ventricle (2.40 Gy vs. 1.34 Gy) compared to those without GLS decline.
“The relative risk increased by a factor between two and four in the subgroup of patients receiving the extra radiation compared to the others,” Dr. Mousseaux said. “This means the more radiation a patient receives during breast cancer radiation therapy, the greater the risk of subsequent decrease in longitudinal function.”
This subgroup also exhibited a significant rise in the left atrial booster function, an indicator of the heart compensating for impaired filling, suggesting possible subclinical diastolic dysfunction.
All of these changes could represent early markers of heart failure with preserved ejection fraction (HFpEF), a condition that is often difficult to detect in its initial stages.