[Results of definitive radiotherapy for squamous cell carcinomas of the larynx patients with subglottic extension].

Background: Squamous cell carcinoma of larynx with subglottic extension is a rare location described to carry a poor prognosis. The aim of this study was to analyze outcomes and feasibility of definitive radiotherapy in patients with squamous cell carcinoma.
Patients and Methods: Between 1998 and 2012, 56 patients with squamous cell carcinoma were treated at our institution and included in the analysis. Patients received definitive radiotherapy/chemoradiotherapy alone (63%) or after induction chemotherapy (37%) at our institute.
Results: The 5-year actuarial overall survival, progression-free survival and specific survival were 64% (CI 95%: 48-90), 45% (CI 95%: 28-61), 88% (CI 95%: 78-98), respectively, with median follow-up of 74 months. The 5-year locoregional control was 69% (CI 95%: 56-83) and the 5-year distant control was 95% (CI 95%: 89-100). There was no difference in overall survival and locoregional control according to front-line treatments or between primary subglottic cancer and glotto-supraglottic cancers with subglottic extension. In the multivariate analysis, performance status of at least 1 and positive N stage were the only predictors for overall survival (hazard ratio [HR] [CI 95%]: 6.5 [1.3-34; P=0.03] and 11 [1.6-75; P=0.02], respectively). No difference of locoregional control was observed according to the first received therapy. The univariate analysis retrieved that T3-T4 patients had a lower locoregional control (HR: 3.1; CI 95%: 1.1-9.2, P=0.04), but no prognostic factor was retrieved in the multivariate analysis. In patients receiving a larynx preservation protocol, 5-year larynx preservation rate was 88% (CI 95%: 78-98), and 58% in T3 patients. The 5-year larynx preservation rate was 91% (CI 95%: 79-100) and 83% (CI 95%: 66-100) for patients who received radiotherapy/chemoradiotherapy or induction chemotherapy as a front-line treatment, respectively.
Conclusion: This analysis suggests that the results for squamous cell carcinoma patients treated with radiotherapy/chemoradiotherapy are comparable to those obtained for other laryngeal tumors. This thus suggests the feasibility of laryngeal preservation protocols for infringement subglottic for selected cases. Further studies are needed to clarify these preliminary data.
(Copyright © 2013 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.)