A 64-year-old woman named J.G. was diagnosed with a right side, node-negative, HER2-positive, hormone-negative (stage I) breast cancer about eight years ago. Following lumpectomy and sentinel node biopsy, she was referred to a medical oncologist at a National Cancer Institute-designated comprehensive cancer center for consultation on the need for adjuvant chemotherapy. The oncologist recommended four cycles of doxorubicin plus cyclophosphamide. Final trials for trastuzumab in the adjuvant setting had not been completed at the time of the consultation. And, because of the small size of the primary tumor (0.8 cm), the oncologist did not recommend trastuzumab, citing evolving concerns about cardiotoxicity related to long-term use of the drug. J.G. had a positive family history of cardiac events: Both of her parents died from sudden myocardial infarctions in their 60s and her older brother had congestive heart failure (CHF). J.G. had a personal history of hypertension (for which she declined antihypertensive treatment), was obese (body mass index of 38.4), and was sedentary. She agreed with the treatment plan as discussed with her oncologist. A prechemotherapy cardiac assessment of an electrocardiogram and multigated acquisition (MUGA) scan showed no cardiac problems. The MUGA scan's result for left ventricular ejection fraction (LVEF) was 61% (normal is 50% or greater). J.G. proceeded with treatment, which she tolerated well. Following chemotherapy, she underwent six weeks of external beam radiation to her right breast with a boost to the tumor site.