Background: Brain metastases (BrM) incidence is 25% to 50% in women with advanced human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Radiation and surgery are currently the main local treatment approaches for central nervous system (CNS) metastases. Systemic anti-HER2 therapy following a diagnosis of BrM improves outcomes. Previous preclinical data has helped elucidate HER2 brain trophism, the blood-brain/blood-tumor barrier(s), and the brain tumor microenvironment, all of which can lead to development of novel therapeutic options.
Recent findings: Several anti-HER2 agents are currently available and reviewed here, some of which have recently shown promising effects in BrM patients, specifically. New strategies driven by and focusing on brain metastasis-specific genomics, immunotherapy, and preventive strategies have shown promising results and are under development.
Conclusions: The field of HER2+ breast cancer, particularly for BrM, continues to evolve as new therapeutic strategies show promising results in recent clinical trials. Increasing inclusion of patients with BrM in clinical studies, and a focus on assessing their outcomes both intracranially and extracranially, is changing the landscape for patients with HER2+ CNS metastases by demonstrating the ability of newer agents to improve outcomes.
Keywords: CNS involvement; HER2-positive breast cancer; T-DM1; brain metastasis; trastuzumab; tucatinib.
© 2020 The Authors. Cancer Reports published by Wiley Periodicals LLC.