(P082) Outcomes of Definitive Radiotherapy for T2N0 Squamous Cell Carcinoma of the Glottis: A Single-Institution Retrospective Study

Bassem Y. Youssef, MD, Abdallah S. Mohamed, MD, MSc, Blaine D. Smith, G. Brandon Gunn, MD, Jack Phan, MD, PhD, William H. Morrison, MD, Adam S. Garden, MD, David I. Rosenthal, MD, Clifton D. Fuller, MD, PhD; UT MD Anderson Cancer Center

BACKGROUND: The aim of this study is to report the oncologic and functional outcomes of patients with T2N0M0 squamous cell carcinoma (SCC) of the glottis treated with radiation therapy (RT).

METHODS: Sequential patients treated with definitive RT for T2 glottic SCC at our facility between 2000 and 2013 were retrospectively reviewed under an approved institutional review board (IRB) protocol. Demographics, disease stage, and treatment characteristics were extracted. Local control and survival outcomes at 2 and 5 years of follow-up were calculated. Both univariate analysis and multivariate Cox proportional hazards assessment were performed to investigate the correlation of patient- and treatment-related factors with disease control and survival endpoints.

RESULTS: A total of 68 patients were included in the analysis. The median follow-up was 55 months (range: 5–173 mo); 58 (85%) of the patients were male, and the median age was 63 years (range: 18–88 yr). Of the 68 patients, 20 (29%) were treated using intensity-modulated radiotherapy (IMRT), and the remainder was treated using conventional three-dimensional conformal radiotherapy (3DCRT). Further, 18 patients (26%) were treated using altered fractions schemes, while the rest were treated conventionally. The local control (LC) and locoregional control (LRC) rates at 2 and 5 years were 89% and 84%, and 87% and 82%, respectively. The rate of ultimate LRC was 100%, with no single second recurrence after successful surgical salvage. The disease-specific survival (DSS) was 95% at both 2 and 5 years, with a corresponding OS of 92% and 88%, respectively. In both univariate and multivariate analyses, none of the examined variables (age, pathologic grade, radiation technique, fractionation scheme, total dose, and chemotherapy) was associated with local recurrence or mortality, except for older age, which was associated with worse OS only in the univariate analysis (P < .0001).Regarding functional outcome, only one patient was feeding tube–dependent at the 1 year follow-up due to persistence of grade 3 dysphagia; 60% of patients had no hoarseness of voice at the last follow-up assessment.

CONCLUSIONS: Excellent 5-year oncologic and functional outcomes were achieved for patients presented in the study. The use of altered fractionation, concurrent chemotherapy, and different radiation techniques did not show any significant differences in outcomes. However, the reduced radiation dose delivered to the carotid arteries using IMRT suggests that it is potentially advantageous for reduction of long-term vascular toxicity and is therefore recommended as the treatment of choice. 

Proceedings of the 97th Annual Meeting of the American Radium Society- americanradiumsociety.org