摘要
Background: Breast cancer (BC) is one of the most common cancers among women in Taiwan, with an increasing incidence rate. Advancements in treatment, particularly new-generation antibody-drug conjugates (ADCs), have shown promise for HER2-low BC. This consensus aims to help clinicians formulate treatment guidelines for HER2-low patients. Methods: The Taiwan Breast Cancer Society convened a multidisciplinary panel to conduct a systematic literature review and discuss nine key topics. The panel utilized the US Preventive Services Task Force and GRADE approach for evidence grading and employed the modified Delphi technique to achieve expert consensus. Results: The panel developed 25 consensus statements regarding ADCs and HER2 status. Key findings include that HER2 expression is necessary for trastuzumab-DM1 (T-DM1) and trastuzumab deruxtecan (T-DXd), while TROP2 testing is not required for sacituzumab govitecan (SG). T-DXd is the preferred second-line treatment for HER2-positive metastatic breast cancer and is effective in HER2-low disease and brain metastases. For HR-positive/HER2-negative metastatic breast cancer, both T-DXd and SG improve outcomes after endocrine therapy and CDK4/6 inhibitors. In triple-negative breast cancer, SG offers significant benefits in refractory cases. For HER2-low breast cancer, T-DXd is considered first in HR-positive cases, and SG in HR-negative cases. The routine sequential use of multiple ADCs is not currently supported by evidence Conclusion: This consensus provides essential insights into HER2-low BC, highlighting its characteristics and evolving treatment options, serving as a practical reference for clinicians.