Cardiac safety evaluation in cancer clinical trials

Identification and quantification of the cardiac adverse effects of new cancer therapeutics is important when comparing treatment arms in clinical trials. Heart failure and left ventricular dysfunction are some of the most common adverse cardiac effects of a range of cancer treatments, including anthracyclines, trastuzumab and other targeted agents. Using the example of trastuzumab-induced cardiac dysfunction, we evaluated phase III clinical trials performed over the past decade to establish the methods used to identify heart failure and impairment of left ventricular function. Both these adverse events are difficult to accurately quantify. A clinical diagnosis of heart failure is subjective, and measurement of left ventricular ejection fraction has high interobserver variability depending on the method used to measure it. We found there was heterogeneity in methods used to diagnose both these adverse events. In addition, the use of quality assurance techniques to reduce measurement variability was low. We discuss and propose methods to standardise and reduce variability of cardiac event assessment in cancer clinical trials. This will allow true comparison of cardiac events between arms and trials with the aim of ensuring cardiac safety data are accurate.