HER2-low/ultralow Breast Cancer Playbook

Course overview

This activity provides practical insights for pathologists and laboratory professionals who are working to improve how they perform HER2 testing in breast cancer and how they are navigating some of the challenges around reporting HER2-low and HER2-ultralow results. Accurately identifying HER2-low and HER2-ultralow status remains a crucial step when determining patient eligibility for FDA-approved therapies like trastuzumab deruxtecan (T-DXd) in the metastatic setting. This activity was developed by interviewing pathology departments across the country and exploring how they are classifying and reporting HER2-low (IHC 1+ or 2+/ISH-negative) and HER2-ultralow (IHC 0 with minimal membrane staining) results in breast cancer.