Matted nodes: High distant-metastasis risk and a potential indication for intensification of systemic therapy in human papillomavirus-related oropharyngeal cancer

Background. The purpose of this study was to determine whether matted nodes uniquely identify patients with human papillomavirus (HPV)-positive oropharyngeal cancer at disproportionately high distant failure risk who may benefit from intensified systemic therapy. Methods. One hundred seventy-eight patients with stage III/IV HPV-positive oropharyngeal cancer who completed definitive chemoradiotherapy were stratified by risk group (low-risk = T1-3/N0-2c/<10 pack-years; intermediate-risk = T1-3/N0-2c/>= 10 pack-years; and high-risk = T4 or N3). Prognostic impact of matted nodes was assessed. Results. At the 52-month median follow-up, event rates with and without matted nodes were: locoregional failure: 23.3% versus 12.8% (p = .16), distant failure: 50.0% versus 1.4% (p < .01), any failure: 73.3% versus 14.2% (p < .01); cause-specific mortality: 56.7% versus 5.4% (p < .01), and death: 56.7% versus 13.5% (p < .01). In multivariate analyses, including risk group and individual risk factors, matted nodes were the strongest predictor for all endpoints except locoregional failure. Among patients without matted nodes, risk-group discriminated locoregional failure (at 3 years: low-risk = 2.0%; intermediate-risk = 14.4%; and high-risk = 24.2%; p < .01), but not distant failure (low-risk 5 0.0%; intermediate-risk = 2.1%; and high-risk 5 3.8%; p = .53). Conclusion. Matted nodes portended dramatically increased distant failure and death risks in HPV-positive oropharyngeal cancer, identifying a candidate population for consideration of chemo-intensification. (C) 2015 Wiley Periodicals, Inc.