1. Head and Neck Surgery Department; Barretos Cancer Hospital; Barretos Brazil
2. Biostatistics Department; Princess Margaret Cancer Centre and Dalla Lana School of Public Health, University of Toronto; Toronto Canada
3. Department of Medicine; Princess Margaret Cancer Centre and Dalla Lana School of Public Health, University of Toronto; Toronto Canada
4. Department of Otolaryngology and Head and Neck Surgery; University Health Network and University of Toronto; Toronto Canada
5. Department of Radiation Oncology; Princess Margaret Cancer Centre, University of Toronto; Toronto Canada