Despite the volume of research and a number of therapeutic options, breast cancer is still a devastating disease for many people afflicted by it. Breast cancer can affect both men and women and is one of the most common forms of cancer in the US, accounting for upwards of a third of newly diagnosed cases. A frequent complication of breast cancer is metastasis, when cells from the primary tumor establish new tumors in other sites around the body. The lungs, brain, bone, and skin are common metastatic sites in patients with breast cancer and are the primary cause of breast-cancer associated mortality.
When it comes to treatment, there are non-specific treatment options, such as radiation and surgery, as well as targeted therapies, which are chosen based on the molecular characteristics of an individual’s tumor. One such factor is the overexpression of a protein called HER2, found in roughly 20% of breast cancer patients. Even with available HER2-targeted drugs that have been successful in improving prognosis, between 30-50% of patients with metastatic HER2-positive disease will still develop brain metastases (BM), which are difficult to treat and associated with poor prognosis. As current treatment options have only managed to provide moderate improvement, there is still a need for new and more effective treatment options for these patients.
