The major limitation in the use of trastuzumab therapy is cardiotoxicity. We evaluated the safety of a strategy of continuing trastuzumab in patients with breast cancer despite mild, asymptomatic left ventricular impairment.
Charts of consecutive patients referred to a cardio-oncology clinic from January 2015 to March 2017 for decline in left ventricular ejection fraction ( lvef), defined as a fall of 10 percentage points or more, or a value of less than 50% during trastuzumab therapy, were reviewed. The primary outcome of interest was change in lvef, measured before and during trastuzumab exposure and up to 3 times after initiation of cardiac medications during a median of 9 months.
All 18 patients referred for decline in lvef chose to remain on trastuzumab and were included. All patients were treated with angiotensin converting–enzyme inhibitors or beta-blockers, or both. After initiation of cardiac medications, lvef increased over time by 4.6 percentage points (95% confidence interval: 1.9 percentage points to 7.4 percentage points), approaching baseline values. Of the 18 patients, 17 (94%) were asymptomatic at all future visits. No deaths occurred in the group.