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

Publication date: Available online 9 January 2017
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Shao Hui Huang, John Waldron, Scott V. Bratman, Jie Su, John Kim, Andrew Bayley, John Cho, Meredith Giuliani, Andrew Hope, Jolie Ringash, Aaron Hansen, John R. de Almeida, David Goldstein, Bayardo Perez-Ordonez, Ilan Weinreb, Li Tong, Wei Xu, Brian O'Sullivan
Purpose/ObjectiveTo report outcome of ipsilateral radiotherapy (RT-ipsi) for HPV-positive [HPV+] and HPV-negative [HPV–] T1-T2N0-N2b tonsil cancer treated 25 years after our initial historical cohort.Materials/MethodsT1-T2N0-N2b tonsil cancer patients receiving RT-ipsi or bilateral RT (RT-bilat) between 1999-2014 were reviewed. Overall survival (OS), local (LC), regional (RC), and grade 3-4 late toxicity (LT) were compared between RT-ipsi vs RT-bilat within HPV+ and HPV– patients, separately.ResultsHPV status was ascertained in 379/427 (88%) consecutive cases (RT-ipsi: 62 HPV+, 34 HPV–; RT-bilat: 240 HPV+ 240, 41 HPV–). Proportion of ipsilateral RT by N-category for HPV+ and HPV– were: N0: 24/37 (65%) vs 28/48 (74%); N1: 21/49 (43%) vs 4/9 (44%); N2a: 10/39 (26%) vs 1/4 (25%); and N2b: 7/177 (4%) vs 1/24 (4%), respectively. 94/96 (98%) RT-ipsi were treated with RT-alone. Median follow-up was 5.03 years. Respective 5-year OS, LC, RC and LT were similar between RT-ipsi vs RT-bilat for the HPV+ [OS: 89% vs 87%, p=0.55; LC: 97% vs 98%, p=0.65; RC: 98% vs 97%, p=0.27; LT: 17% vs 12%, p=0.83] and HPV– [OS: 63% vs 48%, p=0.27; LC: 90% vs 80%, p=0.19; RC: 94% vs 83%, p=0.14; LT: 15% vs 22%, p=0.36]. Of the 96 RT-ipsi patients, contralateral neck failure (CNF) occurred in 1/52 HPV+ 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=0.66]. Five local [2 HPV+; 3 HPV–] and no distant failures were seen. Five-year LC, RC and LT were 97% vs 90% (p=0.24), 98% vs 94% (p=0.25), 18% vs 15% (p=0.75) for the HPV+ and HPV– cohort, respectively. Osteoradionecrosis occurred in 9 patients: 6/47 (13%) treated with conventional RT and 3/49 (6%) with IMRT (p=0.32).ConclusionIpsilateral radiation to selected T1-T2N0-N2b tonsil patients results in equally excellent outcomes regardless of tumor HPV status.

Teaser

This study describes results of ipsilateral radiotherapy for T1-T2N0-N2b tonsil cancer in the HPV era, 25 years after the final accrual of our historical 1970-1991 cohort. It shows equally high loco-regional control and survival for HPV-positive and HPV-negative patients receiving ipsilateral versus bilateral radiotherapy. The original principles of case selection for ipsilateral radiotherapy are discussed and remain universally applicable in the current HPV era.


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