Key clinical point: In this real-world population, low expression of human epidermal growth factor receptor 2 (HER2) did not affect the prognosis of metastatic breast cancer (BC).
Major finding: HER2-low vs HER2-negative disease had no significant effect on the overall survival, neither in hormone receptor-positive (hazard ratio [HR], 0.89; P = .171) nor in triple-negative (HR, 0.92; P = .585) subgroups.
Study details: Findings are from an analysis of 1,973 patients with metastatic BC from the metastatic BC-Registry of the Austrian Study Group of Medical Tumor Therapy (AGMT). Among evaluable patients, 20.3% were HER2-positive, 35.2% were HER2-low, and 44.5% were completely HER2-negative.
Disclosures: The AGMT-MBC-registry is supported by grants from Roche, Daiichi Sankyo, Pfizer, and AstraZeneca. The authors declared expert testimony and/or receiving honoraria, research grants, and travel support from several sources.
Source: Gampenrieder SP et al. Breast Cancer Res. 2021 Dec 14. doi: 10.1186/s13058-021-01492-x .