title: Re-evaluation of Ipsilateral Radiation for T1-T2N0-N2b Tonsil Carcinoma at the Princess Margaret Hospital in the Human Papillomavirus Era, 25 Years Later.
abstract: To report the outcome of ipsilateral radiation therapy (RT) in human papillomavirus (HPV)-positive (HPV+) patients and HPV-negative (HPV-) patients with T1-T2N0-N2b tonsillar cancer treated 25 years after our initial historical cohort.
  
  
  
  Patients with T1-T2N0-N2b tonsillar cancer who received ipsilateral RT or bilateral RT between 1999 and 2014 were reviewed. Overall survival (OS), local control (LC), regional control (RC), and grade 3 to 4 late toxicity (LT) were compared between ipsilateral RT and bilateral RT within HPV+ and HPV- patients, separately.
  
  
  
  HPV status was ascertained in 379/427 (88%) consecutive patients (ipsilateral RT: 62 HPV+, 34 HPV-; bilateral RT: 240 HPV+ 240, 41 HPV-). The proportion of ipsilateral RT by N category for HPV+ and HPV- patients were as follows: N0: 24/37 (65%) versus 28/48 (74%); N1: 21/49 (43%) versus 4/9 (44%); N2a: 10/39 (26%) versus 1/4 (25%); and N2b: 7/177 (4%) versus 1/24 (4%), respectively. Of the patients receiving ipsilateral RT, 94/96 (98%) were treated with RT alone. The median follow-up time was 5.03 years. The respective 5-year rates of OS, LC, RC, and LT were similar between ipsilateral RT and bilateral RT for the HPV+ patients (OS: 89% vs 87%, P=.55; LC: 97% vs 98%, P=.65; RC: 98% vs 97%, P=.27; LT: 17% vs 12%, P=.83) and HPV- patients (OS: 63% vs 48%, P=.27; LC: 90% vs 80%, P=.19; RC: 94% vs 83%, P=.14; LT: 15% vs 22%, P=.36). Of the 96 patients receiving ipsilateral RT, contralateral neck failure (CNF) occurred in 1/52 HPV+ patients and 1/34 HPV- patients. The 5-year CNF rates were 2% (95% CI: 1-9) (HPV+: 2% [0-14]; HPV-: 3% [0-21], P=.66). Five local failures (2 HPV+; 3 HPV-) and no distant failures were seen. The 5-year rates of LC, RC, and LT were 97% versus 90% (P=.24), 98% versus 94% (P=.25), and 18% versus 15% (P=.75) for the HPV+ and HPV- cohorts, respectively. Osteoradionecrosis occurred in 9 patients: 6/47 (13%) treated with conventional RT and 3/49 (6%) with intensity modulated RT (P=.32).
  
  
  
  Ipsilateral radiation to selected patients with T1-T2N0-N2b tonsillar cancer results in equally excellent outcomes regardless of tumor HPV status.
authors.affiliation: Department of Radiation Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada. Electronic address: shaohui.huang@rmp.uhn.on.ca.
authors.forename: Shao Hui
authors.initials: SH
authors.lastname: Huang
authors.affiliation: Department of Radiation Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada; Department of Otolaryngology-Head & Neck Surgery, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Waldron
authors.affiliation: Department of Radiation Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Scott V
authors.initials: SV
authors.lastname: Bratman
authors.affiliation: Department of Biostatistics, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Jie
authors.initials: J
authors.lastname: Su
authors.affiliation: Department of Radiation Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Bayley
authors.affiliation: Department of Radiation Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Cho
authors.affiliation: Department of Radiation Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Meredith
authors.initials: M
authors.lastname: Giuliani
authors.affiliation: Department of Radiation Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hope
authors.affiliation: Department of Radiation Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Jolie
authors.initials: J
authors.lastname: Ringash
authors.affiliation: Division of Medical Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Aaron
authors.initials: A
authors.lastname: Hansen
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: John R
authors.initials: JR
authors.lastname: de Almeida
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Goldstein
authors.affiliation: Department of Pathology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Bayardo
authors.initials: B
authors.lastname: Perez-Ordonez
authors.affiliation: Department of Pathology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Ilan
authors.initials: I
authors.lastname: Weinreb
authors.affiliation: Department of Radiation Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Li
authors.initials: L
authors.lastname: Tong
authors.affiliation: Department of Biostatistics, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Radiation Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada; Department of Otolaryngology-Head & Neck Surgery, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Brian
authors.initials: B
authors.lastname: O'Sullivan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010025:Osteoradionecrosis / Q000209:etiology; D027383:Papillomaviridae; D018579:Patient Selection; D011832:Radiation Injuries / Q000473:pathology; D011878:Radiotherapy / Q000009:adverse effects / Q000379:methods; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods; D012189:Retrospective Studies; D016019:Survival Analysis; D013997:Time Factors; D014067:Tonsillar Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy* / Q000821:virology*; D016896:Treatment Outcome