Grant: Operating Grant: Industry-partnered Collaborative Research - Rx&D partner

About 25-30% of breast cancer patients have a more aggressive type of breast cancer which produces a protein called HER2. New therapy blocking this protein with an antibody (trastuzumab) has shown an approximate 50% reduction in the risk of this aggressive breast cancer from recurring. Trastuzumab is given with standard breast cancer chemotherapy. Unfortunately, one significant side-effect from trastuzumab treatment is potential heart damage leading to heart failure. The exact mechanism of trastuzumab causing heart damage is not well understood. During trastuzumab treatment, the patient's heart is scanned with radiation (MUGA scan) to monitor for any decrease in the strength of the heart pumping. This study will focus on a potentially better way of detecting heart damage using more sophisticated heart MRI scanning (cardiac MRI). Cardiac MRI is superior to MUGA scans in detecting small changes in the heart without the need of radiation exposure. Also, patients will be assessed for any evidence of heart failure, by examining for any symptoms and/or signs of heart failure. Blood tests will also be performed with the heart scans to test for two blood markers of heart damage and heart failure. This information may provide some insights into the mechanism of trastuzumab toxicity to the heart. The results of this study are relevant to breast cancer patients receiving trastuzumab therapy. This study will identify a better way of determining if any heart damage is happening during treatment and try to understand the mechanism involved in heart failure development. The blood markers studied may help determine who is at greater risk of developing heart failure with trastuzumab treatment, and thereby decrease the possibility of developing any heart damage with this therapy.