Prognostic Significance of Hyoid Bone Invasion in Advanced Base of Tongue Carcinoma Treated by Chemoradiation

Abstract

Objectives: Examine the prognostic influence of hyoid bone invasion in advanced base of tongue squamous cell carcinoma (BOTSCC) treated with chemoradiation. Methods: We retrospectively reviewed pre-treatment imaging (computed tomography/magnetic resonance imaging) for the presence or absence of hyoid bone invasion in patients with advanced (T3 or T4a) BOTSCC treated with chemoradiation from January 2001 to January 2011 at our tertiary academic medical center. We compared patients with hyoid bone invasion to those without based on the following metrics: 1-year, 2-year and 5-year disease-free survival (DFS), disease-specific survival, and overall survival. Results: 13 out of 40 patients had hyoid invasion present on pretreatment imaging. Average follow up was 43 months (range: 19-96 months). Patients with hyoid bone invasion were found to have lower percentages in all survival metrics measured compared to patients without, respectively, with statistical significance achieved in the following: 1-year DFS: 53.9% vs. 84.6% ( P = 0.04), 2-year DFS: 36.4% vs. 80.0% ( P = 0.01) and 5-year DFS: 22.2% vs. 62.5% ( P = 0.05). Patients with hyoid bone invasion were also found to have lower percentages in DFS compared to patients without hyoid bone invasion the following subgroups: T4a BOTSCC, N stage 2 only, and positive smoking history. A multivariate analysis did not find hyoid bone invasion as a statistically significant independent variable. Conclusions: Hyoid bone invasion by BOTSCC may indicate a poorer prognosis despite treatment. Hyoid bone invasion may be a possible indication for the intensification of radiation therapy or the addition of chemotherapy, may encourage the consideration of primary surgery, and/or may increase the degree of post-treatment surveillance monitoring and imaging.