HER2-targeted therapies improve outcomes by shutting down growth signaling to cancer cells, targeted delivery of chemotherapy, or blocking intracellular signaling - all leveraging the HER2 receptor to better control metastatic breast cancer.
Sara M. Tolaney, MD, MPH explains that treatment decisions for metastatic breast cancer are based on the current biopsy showing receptor status, but prior biopsies over the full course of disease are considered as well, particularly for HER2 targeted therapies which may work even if HER2 low expression occurred years earlier.
Treatment for HER2-negative metastatic breast cancer depends on factors like hormone receptor status, with chemo/immunotherapy for PD-L1-positive triple negative disease, PARP inhibitors for BRCA mutations, and antibody-drug conjugates as options after first line therapy.
Patients on HER2-targeted therapies for HER2-positive metastatic breast cancer should be vigilant about potential side effects like heart toxicities and interstitial lung disease and should undergo regular heart function monitoring and lung scans to catch these side effects early.
Treatment for HER2 low metastatic breast cancer may utilize HER2-targeted antibody-drug conjugates like T-DM1 and sacituzumab govitecan after initial therapy; knowing HER2 status, even low expression, is critical to guide use of these HER2-directed ADCs after chemotherapy.