What risk increases when trastuzumab is combined with pertuzumab in therapy?

Trastuzumab and pertuzumab are both monoclonal antibodies that target the HER2 protein and are commonly used in the treatment of HER2-positive breast cancer. When these agents are combined in therapy, a notable concern is the potential impact on cardiac function.

The correct answer highlights that combining trastuzumab with pertuzumab increases the risk of left ventricular ejection fraction (LVEF) decline. This is particularly significant because both agents have been associated with cardiotoxicity, and their concurrent use can exacerbate this effect. LVEF is a critical measure of heart health and is important for assessing a patient's risk of heart failure. Monitoring cardiac function is essential in patients receiving this combination therapy, and any signs of decline in LVEF warrant careful management to prevent severe complications.

This information is crucial for healthcare providers as they balance the benefits of effective cancer treatment with the risk of cardiac side effects, emphasizing the need for vigilant monitoring of heart function in patients being treated with these agents together.