Lasham ARamsaroop RWrigley AKnowlton NRadisky DLambertini M2025-03-192025-03-192024-09-20Lasham A, Ramsaroop R, Wrigley A, Knowlton N. (2024). Analysis of HER2-Low Breast Cancer in Aotearoa New Zealand: A Nationwide Retrospective Cohort Study.. Cancers (Basel). 16. 18. (pp. 3204-).2072-6694https://mro.massey.ac.nz/handle/10179/72679OBJECTIVES: To perform the first national analysis of demographic and clinicopathological features associated with the HER2 positive, HER2-low, and HER2-zero invasive breast cancers in New Zealand. The study will reveal the proportion of women who may benefit from new HER2-targeted antibody drug conjugate (ADC) therapies. METHODS: Utilising data from Te Rēhita Mate Ūtaetae (Breast Cancer Foundation NZ National Register), the study analysed data from women diagnosed with invasive breast cancer over a 21-year period. The HER2 status of tumours was classified into three categories-HER2-zero, HER2-low, HER2-positive. RESULTS: From 2009-2021, 94% of women underwent HER2 testing, with 14% diagnosed with HER2-positive breast cancer. For advanced-stage disease, 38% of those formerly classified as HER2-negative were reclassified as HER2-low. Including HER2-positive breast cancers, this indicates that 60% of women with advanced breast cancer may potentially benefit from the new HER2-directed ADCs (approximately 120 women per year). CONCLUSIONS: The findings suggest a significant proportion of women with invasive breast cancer in New Zealand could benefit from new HER2-targeted treatments. There is a need to standardise HER2 testing to enhance personalised treatment and improve outcomes.(c) 2024 The Author/sCC BY 4.0https://creativecommons.org/licenses/by/4.0/Aotearoa New ZealandHER2 testingHER2-low breast cancerantibody-drug conjugates (ADCs)breast cancer treatmentcancer diagnosticsclinical oncologypersonalised medicinetargeted therapyJournal article10.3390/cancers161832042072-6694journal-article3204-https://www.ncbi.nlm.nih.gov/pubmed/393351753204cancers16183204