[1] Barretos Canc Hosp, Head & Neck Surg Dept, Barretos, Brazil
[2] Univ Toronto, Biostat Dept, Princess Margaret Canc Ctr, Toronto, ON, Canada
[3] Univ Toronto, Dalla Lana Sch Publ Hlth, Toronto, ON, Canada
[4] Univ Toronto, Princess Margaret Canc Ctr, Dept Med, Toronto, ON, Canada
[5] Univ Hlth Network, Dept Otolaryngol & Head & Neck Surg, Toronto, ON, Canada
[6] Univ Toronto, Toronto, ON, Canada
[7] Univ Toronto, Dept Radiat Oncol, Princess Margaret Canc Ctr, Toronto, ON, Canada