1
|
Viale G, Basik M, Niikura N, Tokunaga E, Brucker S, Penault-Llorca F, Hayashi N, Sohn J, Teixeira de Sousa R, Brufsky AM, O'Brien CS, Schmitt F, Higgins G, Varghese D, James GD, Moh A, Livingston A, de Giorgio-Miller V. Retrospective study to estimate the prevalence and describe the clinicopathological characteristics, treatments received, and outcomes of HER2-low breast cancer. ESMO Open 2023; 8:101615. [PMID: 37562195 PMCID: PMC10515285 DOI: 10.1016/j.esmoop.2023.101615] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 07/05/2023] [Accepted: 07/08/2023] [Indexed: 08/12/2023] Open
Abstract
BACKGROUND Approximately 80% of all breast cancers (BCs) are currently categorized as human epidermal growth factor receptor 2 (HER2)-negative [immunohistochemistry (IHC) 0, 1+, or 2+/in situ hybridization (ISH) negative]; approximately 60% of BCs traditionally categorized as HER2-negative express low levels of HER2. HER2-low (IHC 1+ or IHC 2+/ISH-) status became clinically actionable with approval of trastuzumab deruxtecan to treat unresectable/metastatic HER2-low BC. Greater understanding of patients with HER2-low disease is urgently needed. PATIENTS AND METHODS This global, multicenter, retrospective study (NCT04807595) included tissue samples from patients with confirmed HER2-negative unresectable/metastatic BC [any hormone receptor (HR) status] diagnosed from 2014 to 2017. Pathologists rescored HER2 IHC-stained slides as HER2-low (IHC 1+ or IHC 2+/ISH-) or HER2 IHC 0 after training on low-end expression scoring using Ventana 4B5 and other assays at local laboratories (13 sites; 10 countries) blinded to historical scores. HER2-low prevalence and concordance between historical scores and rescores were assessed. Demographics, clinicopathological characteristics, treatments, and outcomes were examined. RESULTS In rescored samples from 789 patients with HER2-negative unresectable/metastatic BC, the overall HER2-low prevalence was 67.2% (HR positive, 71.1%; HR negative, 52.8%). Concordance was moderate between historical and rescored HER2 statuses (81.3%; κ = 0.583); positive agreement was numerically higher for HER2-low (87.5%) than HER2 IHC 0 (69.9%). More than 30% of historical IHC 0 cases were rescored as HER2-low overall (all assays) and using Ventana 4B5. There were no notable differences between HER2-low and HER2 IHC 0 in patient characteristics, treatments received, or clinical outcomes. CONCLUSIONS Approximately two-thirds of patients with historically HER2-negative unresectable/metastatic BC may benefit from HER2-low-directed treatments. Our data suggest that HER2 reassessment in patients with historical IHC 0 scores may be considered to help optimize selection of patients for treatment. Further, accurate identification of patients with HER2-low BC may be achieved with standardized pathologist training.
Collapse
Affiliation(s)
- G Viale
- Department of Pathology and Laboratory Medicine, IEO European Institute of Oncology IRCCS, Milan, Italy.
| | - M Basik
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Canada
| | - N Niikura
- Tokai University School of Medicine, Isehara, Kanagawa Prefecture, Japan
| | - E Tokunaga
- National Hospital Organization Kyushu Cancer Center, Fukuoka, Fukuoka Prefecture, Japan
| | - S Brucker
- Research Institute for Women's Health, University of Tübingen, Tübingen, Germany
| | - F Penault-Llorca
- Centre Jean Perrin, Université Clermont Auvergne, INSERM, U1240 Imagerie Moléculaire et Stratégies Théranostiques, Clermont Ferrand, France
| | - N Hayashi
- St Luke's International Hospital, Tokyo, Tokyo Prefecture, Japan
| | - J Sohn
- Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | | | - A M Brufsky
- University of Pittsburgh Medical Center, Magee-Womens Hospital, Pittsburgh, USA
| | - C S O'Brien
- The Christie NHS Foundation Trust, Manchester, UK
| | - F Schmitt
- Medical Faculty of the University of Porto, CINTESIS@RISE (Health Research Network), Molecular Pathology Unit, Ipatimup, Porto, Portugal
| | - G Higgins
- Victorian Cancer Biobank, Melbourne, Australia
| | - D Varghese
- Epidemiology, Global Real World Evidence Generation, OBU Medical, AstraZeneca, Gaithersburg, USA
| | - G D James
- Medical Statistics Consultancy Ltd, London, UK
| | - A Moh
- Daiichi Sankyo, Inc., Basking Ridge, USA
| | - A Livingston
- Global Medical Affairs, Medical Breast, OBU Medical, AstraZeneca, City House, Cambridge, UK
| | - V de Giorgio-Miller
- Global Medical Affairs, Medical Breast, OBU Medical, AstraZeneca, City House, Cambridge, UK
| |
Collapse
|