TY - JOUR
T1 - Survival outcomes for HER2-low breast cancer
T2 - Danish national data
AU - Sode, Michael
AU - Nielsen, Kåre
AU - Jensen, Maj-Britt
AU - Berg, Tobias
AU - Knoop, Ann
AU - Ejlertsen, Bent
AU - Lænkholm, Anne-Vibeke
PY - 2024/11/14
Y1 - 2024/11/14
N2 - BACKGROUND AND PURPOSE: We investigated the prognosis of breast cancer (BC) with low expression of human epidermal growth factor receptor 2 (HER2), as previous studies have found varying impacts on survival of HER2-low BC compared with HER2 0 BC (HER2 IHC score of 0). HER2-low is defined as a score of 1+ or 2+ in an immunohistochemical (IHC) assay without HER2 gene amplification.MATERIALS AND METHODS: Patients with HER2 0 or HER2-low BC from the national Danish Breast Cancer Group database were examined by multivariable survival analysis in a retrospective noninterventional investigation. Patients were grouped as either HER2 0 or HER2-low. The primary endpoint was time to recurrence (TR), and the secondary endpoints were overall survival (OS) and distant recurrence-free interval (DRFI).RESULTS: 41,610 patients were included (12,981 with HER2 0 BC and 28,629 with HER2-low BC). HER2-low BC was associated with a lower risk of recurrence (hazard ratio [HR]: 0.92, p = 0.03). Regarding secondary endpoints, HER2-low disease was linked to improved overall OS (HR: 0.94, p = 0.02). No statistically significant effect of HER2-low was found for DRFI, along with no differential effect of HER2-low according to estrogen receptor (ER) status.INTERPRETATION: HER2-low BC was found to show an improved HR for OS and DRFI compared with HER2 0 BC; however, further studies are need to establish whether it represents a separate biological entity.
AB - BACKGROUND AND PURPOSE: We investigated the prognosis of breast cancer (BC) with low expression of human epidermal growth factor receptor 2 (HER2), as previous studies have found varying impacts on survival of HER2-low BC compared with HER2 0 BC (HER2 IHC score of 0). HER2-low is defined as a score of 1+ or 2+ in an immunohistochemical (IHC) assay without HER2 gene amplification.MATERIALS AND METHODS: Patients with HER2 0 or HER2-low BC from the national Danish Breast Cancer Group database were examined by multivariable survival analysis in a retrospective noninterventional investigation. Patients were grouped as either HER2 0 or HER2-low. The primary endpoint was time to recurrence (TR), and the secondary endpoints were overall survival (OS) and distant recurrence-free interval (DRFI).RESULTS: 41,610 patients were included (12,981 with HER2 0 BC and 28,629 with HER2-low BC). HER2-low BC was associated with a lower risk of recurrence (hazard ratio [HR]: 0.92, p = 0.03). Regarding secondary endpoints, HER2-low disease was linked to improved overall OS (HR: 0.94, p = 0.02). No statistically significant effect of HER2-low was found for DRFI, along with no differential effect of HER2-low according to estrogen receptor (ER) status.INTERPRETATION: HER2-low BC was found to show an improved HR for OS and DRFI compared with HER2 0 BC; however, further studies are need to establish whether it represents a separate biological entity.
KW - Humans
KW - Female
KW - Breast Neoplasms/mortality
KW - Receptor, ErbB-2/metabolism
KW - Denmark/epidemiology
KW - Middle Aged
KW - Aged
KW - Retrospective Studies
KW - Adult
KW - Prognosis
KW - Neoplasm Recurrence, Local/pathology
KW - Aged, 80 and over
KW - Biomarkers, Tumor/metabolism
KW - Receptors, Estrogen/metabolism
U2 - 10.2340/1651-226X.2024.41280
DO - 10.2340/1651-226X.2024.41280
M3 - Article
C2 - 39543845
SN - 0284-186X
VL - 63
SP - 878
EP - 886
JO - Acta Oncologica
JF - Acta Oncologica
ER -