Re-evaluation of Ipsilateral Radiation for T1-T2N0-N2b Tonsil Carcinoma at the Princess Margaret Hospital in the Human Papillomavirus Era, 25 Years Later

Journal Article · Mon May 01 04:00:00 EDT 2017 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2017.01.018· OSTI ID:22649919

Waldron, John ^[1]; Bratman, Scott V. ^[1]; Su, Jie ^[2]; Kim, John; Bayley, Andrew; Cho, John; Giuliani, Meredith; Hope, Andrew; Ringash, Jolie ^[1]; Hansen, Aaron ^[3]; Almeida, John R. de; Goldstein, David ^[4]; Perez-Ordonez, Bayardo; Weinreb, Ilan ^[5]; Tong, Li ^[1]; Xu, Wei ^[2]; O'Sullivan, Brian ^[1]

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1. Department of Radiation Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada)
2. Department of Biostatistics, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada)
3. Division of Medical Oncology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada)
4. Department of Otolaryngology—Head & Neck Surgery, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada)
5. Department of Pathology, The Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario (Canada)

Purpose: 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. Methods and Materials: 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. Results: 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). Conclusion: Ipsilateral radiation to selected patients with T1-T2N0-N2b tonsillar cancer results in equally excellent outcomes regardless of tumor HPV status.

• OSTI ID: 22649919
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 1 Vol. 98; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

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