[1] Univ Toronto, Univ Hlth Network, Princess Margaret Canc Ctr, Dept Otolaryngol Head & Neck Surg, 200 Elizabeth St, Toronto, ON M5G 2C4, Canada
[2] Univ Hlth Network, Princess Margaret Canc Ctr, Dept Surg Oncol, Toronto, ON, Canada
[3] Univ Toronto, Interdept Div Crit Care Med, Toronto, ON, Canada
[4] Univ Hlth Network, Dept Biostat, Princess Margaret Hosp, Toronto, ON, Canada
[5] Univ Toronto, Dalla Lana Sch Publ Hlth, Toronto, ON, Canada
[6] Univ Toronto, Dept Med, Toronto, ON, Canada
[7] Univ Toronto, Inst Hlth Policy Management & Evaluat, Toronto, ON, Canada
[8] Univ Toronto, Inst Med Sci, Toronto, ON, Canada