Comparison of high-dose Cisplatin-based chemoradiotherapy and Cetuximab-based bioradiotherapy for p16-positive oropharyngeal squamous cell carcinoma in the context of revised HPV-based staging

Aim: To perform a comparison of Cisplatin vs. Cetuximab in p16-positive oropharyngeal squamous cell carcinoma (OPSCC) in the context of the revised HPV-based staging. Background: Previous reports comparing these agents in head and neck cancer have included heterogenous disease and p16-status. Materials and methods: A retrospective review was conducted from 2006 to 2016 of patients with p16-positive OPSCC who underwent definitive radiotherapy concurrent with either triweekly Cisplatin (n=251.) or Cetuximab (n=40). AJCC 8th Edition staging was adapted. Results: Median follow-up for surviving patients was 40 months. On multivariate analysis for all-comers, comparing Cisplatin and Cetuximab, 3-year locoregional recurrence (LRR): 6% vs. 16% (p = 0.07), 3-year distant metastasis (DM): 8% vs. 21% (p = 0.04), 3-year overall recurrence rate (ORR): 11% vs. 29% (p = 0.01), and 3-year cause-specific survival (CSS): 94% vs. 79% (p = 0.06), respectively. On stage-based subgroup analysis, for stage I-II disease, 3-year LRR: 5% vs. 10% (p = 0.51), 3-year DM: 7% vs. 16% (p = 0.32), 3-year ORR: 10% vs. 23% (p = 0.15), and 3-year CSS: 95% vs. 82% (p = 0.38). For stage III disease, 3-year LRR: 10% vs. 40% (p = 0.07), 3-year DM: 9% vs. 43% (p = 0.07), 3-year ORR: 15% vs. 55% (p = 0.04), and 3-year CSS: 94% vs. 57% (p = 0.048). Conclusions: When given concurrently with radiotherapy, Cetuximab and triweekly Cisplatin demonstrated comparable efficacy for AJCC 8th Edition stage I-II p16-positive OPSCC. However, Cetuximab appeared to be associated with higher rates of treatment failure and cancer-related deaths in stage III disease. Upon availability of the RTOG 1016 trial results, analysis based on the revised HPV-based staging should be performed to confirm these findings. (C) 2018 Greater Poland Cancer Centre. Published by Elsevier Sp. z o.o. All rights reserved.