Postoperative interstitial brachytherapy for resectable squamous cell carcinoma of the tongue.

ABSTRACT

PURPOSE: To evaluate the efficiency and toxicity of postoperative brachytherapy (POBT) in the treatment of resectable mobile tongue squamous cell carcinoma. PATIENTS AND METHODS: This was a retrospective single-center study of patients with SSC of the mobile tongue who were treated between August 1992 and June 2013 by glossectomy and neck dissection followed by (192)Ir interstitial brachytherapy of the tumor bed. Endpoints were local control, cancer-specific survival (CSS), overall survival (OS), and morbidity. Independent prognostic factors were analyzed in a Cox regression model. RESULTS: A total of 112 patients were identified (median age, 55 years [range, 15-84]; 76% male). Patient and tumor characteristics were T1T2N0 (85%), pN+ (13%), positive surgical margins (14%), negative margins <5 mm (29%), dysplasic margins (14%), lymphatic vessel invasion (5%), and perineural spread (5%). Median followup was 6.7 years (1.5 months to 17.7 years). Local control, CSS, and OS rates at 2 years were 79%, 81%, and 72%, respectively. The corresponding 5-year rates were 76%, 67%, and 56%, respectively. After POBT, 22% of patients presented grade ≥2 necrosis and 8% experienced chronic pain. Independent prognostic factors were positive surgical margins for poor local control and tumor recurrence and lymphatic vessel invasion for poor OS. CONCLUSION: POBT provided good local control and better CSS and OS than reported for surgery alone. Morbidity was higher than that reported for brachytherapy alone but may be considered acceptable in a well-selected patient population at high risk of local recurrence.