ESMO Expert Consensus Statements on on the definition, diagnosis, and management of HER2-low breast cancer
Published 01 June 2023 - Ann Oncol
Authors: Paolo Tarantino, Giuseppe Viale, Michael F. Press, Xichun Hu, Frederique Penault Llorca, Aditya Bardia, Anna Batistatou, Harold J. Burstein, Lisa A. Carey, Javier Cortes, Carsten Denkert, Véronique Diéras, William Jacot, Angelos K. Koutras, Annette Lebeau, Sibylle Loibl, Shanu Modi, Maria Fernanda Mosele, Elena Provenzano, Giancarlo Pruneri, Jorge S. Reis Filho, Federico Rojo, Roberto Salgado, Peter Schmid, Stuart J. Schnitt, Sara M. Tolaney, Dario Trapani, Anne Vincent-Salomon, Antonio C Wolff, George Pentheroudakis, Fabrice André, Giuseppe Curigliano
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 9 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 manuscript presents the developed statements, including findings from the expert panel discussions, expert opinion and a summary of evidence supporting each statement.