High-dose-rate interstitial brachytherapy boost in inoperable locally advanced tongue carcinoma

Locally advanced tongue carcinomas (LATCs) in inoperable lesions are managed with external beam radiation therapy (EBRT) and chemotherapy. In our institution, the boost to the gross tumor volume is delivered with high-dose-rate brachytherapy (HDR-BT) after EBRT. We review the outcome of these patients when HDR-BT is added as a boost.

From May 2000 to December 2014, a total of 24 patients with LATC, nonsurgical oral tongue, and base of tongue carcinomas were treated with EBRT and with interstitial plastic tubes for brachytherapy; median dose was 18-24 Gy in 6-8 fractions after 50-60 Gy of EBRT. Mean age was 60 years, 20 men and 4 women. The distribution by stages was 11 patients in Stage III and 13 patients in Stage IV. All cases but one received chemotherapy.

With a median followup of 44 months, local control (LC) rate at 4 years was 80% for the entire group, 78% in Stage III, and 90% in Stage IV. The cause-specific survival was 68% at 4 years; the regional control was 76%. Four patients developed distant metastasis with disease free from distant metastasis of 77% at 4 years. The overall survival was 68% at 4 years.

HDR-BT yields similar results to low dose rate in treatment of patients with LATC, with better results than those reported with exclusive EBRT. HDR-BT allows to increase the local dose, with good LC rates. In patients with large tumors requiring very mutilating surgery and patients who refuse surgery, EBRT with HDR-BT boost is a good option to increase the LC and cause-specific survival while keeping a better functional outcome.