1. Endoscopy Unit, Instituto do Cancer do Estado de Sao Paulo ICESP, Hospital das Clinicas HCFMUSP, Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, Brazil
2. Department of Gastroenterology, Instituto do Cancer do Estado de Sao Paulo ICESP, Hospital das Clinicas HCFMUSP, Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, Brazil
3. Division of Gastroenterology, McGill University Health Centre, McGill University, Montréal, Quebec, Canada
4. Department of Clinical Epidemiology, McGill University, Montréal, Quebec, Canada