Long-term regional control after radiation therapy and neck dissection for squamous cell carcinoma of the base of tongue

Purpose: Minimal literature exists with 10-year data on neck control in advanced head and neck cancer. The purpose of this study was to determine long-term regional control for patients with base of tongue carcinoma who were treated with primary radiation therapy plus neck dissection. Materials and Methods: Between 1981-1996, 68 patients with squamous cell carcinoma of the base of tongue were treated with primary radiation therapy, plus neck dissection for those who presented with palpable lymph node metastases. The T-stage distribution was T1-17, T2-32, T3-17, and T4-2. The N-stage distribution for the 58 patients with clinically positive necks was N1-24, N2a-6, N2b-11, N2c-8, N3-7, and Nx-2. Ages ranged from 35 to 77 (median 55 years) among the 59 males and 9 females. Therapy generally consisted of initial external beam irradiation to the primary site (54 Gy) and neck (50 Gy). All patients who presented with clinically positive necks were boosted to 60 Gy with external beam irradiation. Three weeks later, the base of tongue was boosted with an Ir-192 interstitial implant (20-30 Gy). A neck dissection was done at the same time for those with clinically positive necks, even if a complete clinical neck response was achieved with external beam irradiation. Neoadjuvant cisplatin-based chemotherapy was administered to 9 patients who would have required a total laryngectomy if their primary tumors had been surgically managed. The median follow-up was 36 months, with a range from 1 to 151 months. Eleven patients were followed for over 8 years. No patients were lost to follow-up. Results: Actuarial 5 and 10-year neck control was 96%. Pathologically negative neck specimens were observed in 78% of necks dissected after external beam irradiation. These specimens typically contained only necrosis and/or fibrosis. The remaining 22% of dissected necks were pathologically positive. These specimens contained multiple positive nodes in 63% despite a 55% complete clinical neck response rate to irradiation. Regional failure occurred in only 2 patients. Symptomatic neck fibrosis (RTOG grade 3) was not observed. Actuarial 5 and 10-year local control was 88% and 88%, disease-free survival was 80% and 67%, and overall survival was 86% and 52%. Conclusions: For base of tongue cancer, almost all patients can obtain long-term regional control with no severe complications after definitive radiation therapy, plus neck dissection for those who present with lymphadenopathy. Complete clinical regression of palpable neck metastases after irradiation poorly correlates with pathologic outcome. Our current policy is to include neck dissection at the time of implantation for patients who present with palpable neck metastases. We realize that this therapeutic approach may overtreat some patients, but we are reluctant to change our policy in light of these excellent outcomes