Brain Metastases in HER2-Positive Breast Cancer: Current and Novel Treatment Strategies

Simple Summary Development of brain metastases is an important event for patients with breast cancer, and it affects both their survival and their quality of life. Patients with HER2-positive breast cancer are more commonly affected by brain metastases compared to patients with HER2-negative/hormone receptor-positive breast cancer. It is essential to find proper therapies that reduce the risk for metastasis in the brain, as well as agents that are active when metastatic lesions develop. Management of HER2-positive breast cancer has drastically improved in recent years due to the development of several drugs targeting the HER2 receptor. This review aims to provide insight into current and novel treatment strategies for patients with brain metastases from HER2-positive breast cancer. Development of brain metastases can occur in up to 30-50% of patients with breast cancer, representing a significant impact on an individual patient in terms of survival and quality of life. Patients with HER2-positive breast cancer have an increased risk of developing brain metastases; however, screening for brain metastases is not currently recommended due to the lack of robust evidence to support survival benefit. In recent years, several novel anti-HER2 agents have led to significant improvements in the outcomes of HER2-positive metastatic breast cancer. Despite these advances, brain and leptomeningeal metastases from HER2-positive breast cancer remain a significant cause of morbidity and mortality, and their optimal management remains an unmet need. This review presents an update on the current and novel treatment strategies for patients with brain metastases from HER2-positive breast cancer and discusses the open questions in the field.