Biomarkers and Cardiac MRI as Early Indicators of Cardiac Exposure Following Breast Radiotherapy

Radiotherapy plays an integral role in breast cancer therapy. Multiple randomized studies
have demonstrated decreased local-regional recurrence rates and decreased breast-cancer
mortality. However, balanced with this survival benefit is the potential toxicity of the
treatment itself. In particular, cardiac effects of radiotherapy have been a concern and an
area of research for the past 20 years. From long-term follow up of patients with lymphoma,
it is known that radiotherapy can lead to increased risk of myocardial infarction, valvular
dysfunction, systolic and diastolic function abnormalities, and heart failure among
cancer-survivors. Patients with breast cancer receive lower doses to smaller volumes of the
heart, but they also have an excellent long-term survival, so it is crucial to study the
effects of low dose radiotherapy. Indeed, a recent study suggests that these effects can be
seen within the first 5 years after treatment, and that there is no dose threshold. The
investigators hypothesize that they can develop imaging and blood biomarkers of cardiac
exposure, as a first step to identifying patients at increased risk for cardiac effects.
These patients can then be targeted for close monitoring and early intervention, potentially
with statins or ACE inhibitors. Additionally, by characterizing a time-course and radiation
dose-volume relationship, potentially real-time modifications can be made to RT field design
for patients sensitive to RT effects. Finally, this information can be incorporated into
better designs of treatment plans for future patients.

Inclusion Criteria:

- Patients who will receive RT for left-sided breast cancer and can have a
contrast-enhanced MRI are eligible.

Exclusion Criteria:

- Patients who have a contraindication to contrast-enhanced MRI are not eligible.