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ESMO expert consensus statements (ECS) on the definition, diagnosis, and management of HER2-low breast cancer
P Tarantino1, G Viale2, M F Press3
1Department of Medical Oncology, Dana-Farber Cancer Institute, Boston; Harvard Medical School, Boston, USA; Department of Oncology and Hemato-Oncology, University of Milan, Milan.
Abstract:
Human epidermal growth factor receptor 2 (HER2)-low breast cancer has recently emerged as a targetable subset of breast tumors, based on the evidence from clinical trials of novel anti-HER2 antibody-drug conjugates. This evolution has raised several biological and clinical questions, warranting the establishment of consensus to optimally treat patients with HER2-low breast tumors. Between 2022 and 2023, the European Society for Medical Oncology (ESMO) held a virtual consensus-building process focused on HER2-low breast cancer. The consensus included a multidisciplinary panel of 32 leading experts in the management of breast cancer from nine different countries. The aim of the consensus was to develop statements on topics that are not covered in detail in the current ESMO Clinical Practice Guideline. The main topics identified for discussion were (i) biology of HER2-low breast cancer; (ii) pathologic diagnosis of HER2-low breast cancer; (iii) clinical management of HER2-low metastatic breast cancer; and (iv) clinical trial design for HER2-low breast cancer. The expert panel was divided into four working groups to address questions relating to one of the four topics outlined above. A review of the relevant scientific literature was conducted in advance. Consensus statements were developed by the working groups and then presented to the entire panel for further discussion and amendment before voting. This article presents the developed statements, including findings from the expert panel discussions, expert opinion, and a summary of evidence supporting each statement.
Insights
A European consensus established guidelines for treating Human Epidermal Growth Factor Receptor 2 (HER2)-low breast cancer, a newly targetable tumor subset. Experts addressed biology, diagnosis, and management of HER2-low breast cancer.
Area of Science:
- Oncology
- Translational Research
- Genomics
Background:
- Human Epidermal Growth Factor Receptor 2 (HER2)-low breast cancer is a novel, targetable subtype.
- Emerging anti-HER2 antibody-drug conjugates necessitate consensus on optimal patient management.
- Existing guidelines lack detailed recommendations for this specific breast cancer subset.
Approach:
- A European Society for Medical Oncology (ESMO) virtual consensus process convened 32 multidisciplinary experts from nine countries (2022-2023).
- Four working groups focused on HER2-low breast cancer biology, pathology, metastatic treatment, and clinical trial design.
- Consensus statements were developed through literature review, expert discussion, amendment, and voting.
Key Points:
- The consensus addresses critical biological and clinical questions surrounding HER2-low breast cancer.
- Expert-driven statements provide guidance on diagnosis and management strategies.
- Recommendations cover pathology, clinical management of metastatic disease, and future clinical trial design.
Conclusions:
- This consensus provides crucial guidance for the optimal treatment of patients with HER2-low breast cancer.
- The developed statements aim to standardize care and inform future research in this evolving field.
- The findings support the growing importance of HER2-low status in breast cancer treatment paradigms.
