Prognostic impact of extranodal extension in resected head and neck squamous cell carcinomas in the era of postoperative chemoradiation: A retrospective monocentric study.

Background: For patients with locally advanced head and neck squamous cell carcinoma (LAHNSCC), surgery (S) followed by radiotherapy (RT) is a standard of care. Randomized controlled trials have shown that postoperative chemoradiation (CRT) increased the locoregional control (LRC) and overall survival (OS) in patient with R1-resection margin and/or extranodal extension (ENE). ENE has been introduced in the 8th TNM staging classification since its presence has been shown to have an independent adverse prognostic impact. The data supporting this finding were however mainly collected in the pre-CRT era.
Objectives: The objective of this study was to challenge the adverse prognostic factor of ENE in the era of CRT.
Methods: A retrospective cohort study was performed to evaluate patients diagnosed with LAHNSCC and undergoing a treatment by S and postoperative RT or CRT in Centre Léon Bérard, Lyon, France between 2003 and 2018. Patients with oral cavity, oropharyngeal, laryngeal and hypopharyngeal SCC were included.
Results: 439 patients were included in the study. For patients with non-oropharyngeal p16-positive tumors without ENE, five-year OS, local control, and regional control (RC) reached 63.7%, 86.1%, and 94.9%, respectively; corresponding figures for patients with ENE reached, 42.6%, 77.5%, and 81.1%, respectively (p-value of 0.0006, 0.167, and 0.0005). In multivariable analysis, for non-oropharyngeal p16-positive tumors, ENE remained a poor prognostic factor for OS (RR = 1.74, 95%, CI = 1.16-2.61, p = 0.0069) and RC (RR 3.60, 95% CI =: 1.64-7.87, p = 0.0013).
Conclusion: In the era or postoperative chemoradiation, pathological ENE remains an adverse prognostic factor for OS and RC.
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