[1] Univ Toronto, Univ Hlth Network, Princess Margaret Canc Ctr, Dept Otolaryngol Head & Neck Surg,Surg Oncol, 610 Univ Ave,3-955, Toronto, ON M5G 2M9, Canada
[2] Univ Toronto, Inst Hlth Policy Management & Evaluat, Toronto, ON, Canada
[3] Princess Margaret Canc Ctr, Dept Radiat Oncol, 610 Univ Ave, Toronto, ON M5G 2M9, Canada
[4] Princess Margaret Canc Ctr, Radiat Med Program, 610 Univ Ave, Toronto, ON M5G 2C4, Canada
[5] Univ Toronto, Mt Sinai Hosp, Dept Otolaryngol Head & Neck Surg, 600 Univ Ave, Toronto, ON M5G 1X5, Canada
[6] Univ Toronto, Princess Margaret Canc Ctr, Dept Biostat, 610 Univ Ave, Toronto, ON M5G 2C4, Canada
[7] Univ Toronto, Dalla Lana Sch Publ Hlth, 610 Univ Ave, Toronto, ON M5G 2C4, Canada