Landscape of HER2-low metastatic breast cancer (MBC): results from the Austrian AGMT_MBC-Registry

Breast Cancer Research

Christopher Hager¹  Michael Knauer²  Daniel Egle³  Michael Hubalek⁴  Clemens Schmitt⁵  Margit Sandholzer⁶  Florian Roitner⁷  Johannes Andel⁸  Simon Peter Gampenrieder⁹  Gabriel Rinnerthaler⁹  Richard Greil⁹  Sonja Heibl^1,10  August Felix Zabernigg^1,11  Christian Fridolin Singer^1,12  Marija Balic^1,13  Christoph Tinchon^1,14  Andreas Petzer^1,15 

[1] Breast Center Dornbirn, Dornbirn, Austria;Breast Center Eastern Switzerland, St. Gallen, Switzerland;Department of Gynaecology, Medical University Innsbruck, Innsbruck, Austria;Department of Gynecology, Breast Health Center Schwaz, Schwaz, Austria;Department of Hematology and Internal Oncology, Kepler University Hospital, Johannes Kepler University Linz, Linz, Austria;Department of Internal Medicine II, Academic Teaching Hospital Feldkirch, Feldkirch, Austria;Department of Internal Medicine II, Hospital Braunau, Braunau, Austria;Department of Internal Medicine II, Pyrn-Eisenwurzen Klinikum Steyr, Steyr, Austria;Department of Internal Medicine III With Haematology, Medical Oncology, Haemostaseology, Infectiology and Rheumatology, Oncologic Center, Paracelsus Medical University Salzburg, Müllner Hauptstraße 48, 5020, Salzburg, Austria;Laboratory for Immunological and Molecular Cancer Research (LIMCR) and Center for Clinical Cancer and Immunology Trials (CCCIT), Salzburg Cancer Research Institute (SCRI), Salzburg, Austria;Cancer Cluster Salzburg, Salzburg, Austria;Department of Internal Medicine IV, Klinikum Wels-Grieskirchen GmbH, Wels, Austria;Department of Internal Medicine, County Hospital Kufstein, Kufstein, Austria;Department of Obstetrics and Gynecology and Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria;Division of Oncology, Department for Internal Medicine, Medical University Graz, Graz, Austria;Internal Medicine - Department for Haemato-Oncology, LKH Hochsteiermark-Leoben, Leoben, Austria;Internal Medicine I for Hematology With Stem Cell Transplantation, Hemostaseology and Medical Oncology, Ordensklinikum Linz Barmherzige Schwestern – Elisabethinen, Linz, Austria;

关键词: Metastatic breast cancer;    HER2-low;    HER2-positive;    HER2-negative;    OS;    PFS;    Registry;    Real-world data;   

DOI  :  10.1186/s13058-021-01492-x

来源: Springer

【 摘 要 】

BackgroundAbout 50% of all primary breast cancers show a low-level expression of HER2 (HER2-low), defined as immunohistochemically 1+ or 2+ and lack of HER2 gene amplification measured by in situ hybridization. This low HER2 expression is a promising new target for antibody–drug conjugates (ADCs) currently under investigation. Until now, little is known about the frequency and the prognostic value of low HER2-expression in metastatic breast cancer (MBC).Patients and methodsThe MBC-Registry of the Austrian Study Group of Medical Tumor Therapy (AGMT) is a multicenter nationwide ongoing registry for MBC patients in Austria. Unadjusted, univariate survival probabilities of progression-free survival (PFS) and overall survival (OS) were calculated by the Kaplan–Meier method and compared by the log-rank test. Multivariable adjusted hazard ratios were estimated by Cox regression models. In this analysis, only patients with known HER2 status and available survival data were included.ResultsAs of 11/15/2020, 1,973 patients were included in the AGMT-MBC-Registry. Out of 1,729 evaluable patients, 351 (20.3%) were HER2-positive, 608 (35.2%) were HER2-low and 770 (44.5%) were completely HER2-negative (HER2-0). Low HER2-expression was markedly more frequent in the hormone-receptor(HR)+ subgroup compared to the triple-negative subgroup (40% vs. 23%). In multivariable analysis, low HER2 expression did not significantly influence OS neither in the HR+ (HR 0.89; 95% CI 0.74–1.05; P = 0.171) nor in the triple-negative subgroup (HR 0.92; 95% CI 0.68–1.25; P = 0.585), when compared to completely HER2-negative disease. Similar results were observed when HER2 IHC 2+ patients were compared to IHC 1+ or 0 patients.ConclusionLow-HER2 expression did not have any impact on prognosis of metastatic breast cancer in this real-world population.

【 授权许可】

CC BY