Treatment outcomes of external-beam radiotherapy for squamous cell carcinoma of the base of the tongue

To evaluate definitive external-beam radiotherapy (EBRT) for patients with base of the tongue (BOT) cancers. We reviewed results for 26 patients with BOT cancers who were treated with EBRT. Clinical stages T1, T2, T3, and T4a were observed for 10, 7, 4, and 5 patients, respectively, and stages N0, N1, N2a, N2b, N2c, and N3 were observed for 4, 2, 5, 6, 8, and 1 patients, respectively. More than half of the patients (n = 19) were stage IVA. Standard total delivered doses were 70 Gy to primary tumors and cervical lymph node (CLN) metastases and 40-46 Gy to elective nodal regions. Eleven patients with advanced loco-regional disease received concurrent or neoadjuvant chemotherapy. Four T3 patients and one T2 patient received 2 or 3 cycles of concurrent intra-arterial cisplatin with EBRT (RADPLAT). Three-year overall survival was 69 % (95 % CI 47-83 %), with a median follow-up period of 33 months. Three-year local control was 100, 86, 100, and 20 % for T1, T2, T3, and T4 patients, respectively. Three-year regional control was 100 % for N0, N1, and N2a, 83 % for N2b, 75 % for N2c, and 0 % for N3 patients. Treatment failed for 7 patients. All 5 patients undergoing RADPLAT achieved complete responses and did not develop local recurrence. We achieved favorable outcomes for patients with T1-T3 BOT cancers by use of definitive EBRT with or without chemotherapy.