Effect of Dose to the Heart and Cardiac Substructures on Cardiac Toxicity after Breast Cancer Radiation.

We have identified multiple dosimetric variables for the heart and its substructures which were associated with increased risk of mortality after breast cancer radiation. In fact, for certain structures, there were multiple exposure thresholds which showed increased risk of toxicity, highlighting the complex relationship between substructure dose and outcomes. Further study into these relationships will identify the most critical cardiac substructure constraints that could be used in radiation treatment planning.