Survival and Functional Outcome after Treatment for Primary Base of Tongue Cancer: A Comparison of Definitive Chemoradiotherapy versus Surgery Followed by Adjuvant Radiotherapy

PURPOSE: The purpose of this study was to compare the clinical and functional outcomes in patients with primary base of tongue (BOT) cancer who received definitive radiotherapy (RT) or surgery followed by radiotherapy (SRT). MATERIALS AND METHODS: Between January 2002 and December 2016, 102 patients with stage I-IVB primary BOT cancer underwent either definitive RT (n=46) or SRT (n=56), and treatment outcomes were compared between two groups. The expression of p16 was also analyzed. RESULTS: The RT group had more patients with advanced T stage (T3-4) disease (58.7% vs. 35.7%, p=0.021) and who received chemotherapy (91.3% vs. 37.5%, p < 0.001) than the SRT group. At a median follow up of 36.9 months (range, 3.3 to 181.5 months), the 5-year overall survival (OS) and disease-free survival (DFS) were 75.5% and 68.7%, respectively. With respect to treatment group, the 5-year OS and DFS in the RT and SRT groups did not differ significantly (OS, 68.7% vs. 80.5%, p=0.601; DFS, 63.1% vs. 73.1%, p=0.653). In multivariate analysis, OS differed significantly according to p16 expression (p16-negative vs. p16-positive; hazard ratio [HR], 0.145; 95% confidence interval [CI], 0.025 to 0.853; p=0.033). Regarding DFS, p16 expression (p16-negative vs. p16-positive; HR, 0.164; 95% CI, 0.045 to 0.598; p=0.006) showed a significant effect in multivariate analysis. Functional defects (late grade ≥ 3 dysphagia or voice alteration) were more frequently reported in the SRT than in the RT group (16.1% vs. 2.2%, p=0.021). CONCLUSION: Despite advanced disease, patients in the RT group showed comparable survival outcomes and better functional preservation than those in the SRT group.