Adi Klil-Drori1, Laurent Azoulay2. 1. Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, Montreal, Canada2Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada. 2. Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, Montreal, Canada3Department of Oncology, McGill University, Montreal, Quebec, Canada.