1. Department of Otolaryngology–Head and Neck SurgeryUniversity Health Network Toronto Ontario Canada
2. Sidney Head and Neck Cancer InstituteChris O'Brien Lifehouse Sydney Australia
3. Department of Otorhinolaryngology–Head and Neck SurgeryUniversity of Helsinki and Helsinki University Hospital Helsinki Finland
4. Department of StatisticsPrincess Margaret Cancer Center Toronto Ontario Canada
5. Division of Thoracic Surgery, Department of SurgeryUniversity Health Network Toronto Ontario Canada