Born in 1966 in Cameroon, Etienne Brain has been working since 1998 as a medical oncologist at the Hôpital René Huguenin (Saint-Cloud, France), now part of Institut Curie following the merge between both institutions in 2010. He obtained his MD in Medical Oncology (1993) and a PhD (2005) from Paris-Descartes University, after preclinical and clinical works on alkylation in France and US (Dana Farber Cancer Institute & Boston University 1995-1996). In 2010, he was empowered to supervise research by Versailles/Saint-Quentin University. He has a diploma in Management and Health Economics from Bocconi University, Milan (2014-2015). He is committed to clinical research in breast cancer and older populations, through the networks of the cooperative groups Unicancer (past chair of the GERICO committee dedicated to clinical research in geriatric oncology), the European Organisation for Research and Treatment of Cancer (EORTC) (past-chair of the breast cancer group), and the Breast International Group (BIG, executive board member). His most recent interest focuses on the influence of competing risks for mortality on adjuvant systemic treatment in older breast cancer patients. This is best embodied in the national program ASTER 70s (Adjuvant Systemic Treatment for ER+ HER2- breast carcinoma in women over 70 according to genomic grade: endocrine treatment ± chemotherapy, 2000 women enrolled between 2012 and 2016 in FR and BE) granted in 2011 by the French health ministry. He currently chairs the intergroup of clinical research in geriatric oncology DIALOG labeled by the Institut National du Cancer (INCa). He is a member of the Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) steering committee. He is an executive board member of the European Breast Cancer Council (EBCC) and EORTC, of which he is secretary general since 2021. He is an active member of the American Society of Clinical Oncology (ASCO), the European Society of Medical Oncology (ESMO), and was president of the International Society of Geriatric Oncology (SIOG) from 2014-2016. He is the co-organizer of the yearly SIOG International Course in Geriatric Oncology (Treviso, IT) with the Università Cattolica del Sacro Cuore, that has welcomed more than 200 international delegates from the world of oncology and geriatrics. He is (co)author of several publications in peer-reviewed journals, including the JAMA, Lancet Oncol and J Clin Oncol. He is member of the Editorial Board of the J Geriatric Oncol and The Breast.