Combined external radiotherapy and single-fraction palliative high-dose-rate interstitial brachytherapy for a patient with a base of tongue cancer who had a previous radiation history.

Only a few studies have explored whether high-dose-rate interstitial brachytherapy (HDR-ISBT) can be indicated as a palliative/symptomatic treatment. We present the good results of palliative treatment using HDR-ISBT combined with external beam radiotherapy (ERT) in a patient of base of tongue cancer (cT4aN1M0). The patient was an 81-year-old male who complained of local pain. He had a previous irradiation history for head and neck cancer receiving ERT with systemic chemotherapy and radical surgery 15 years ago. Since it might be difficult for him to receive radical radiation doses using ERT alone, palliative ERT of relatively lower doses of 37.5 Gy in 15 fractions was selected. One month after ERT, HDR-ISBT was implemented as a booster. Considering the burden on physical condition, single-fraction HDR-ISBT was selected. We employed a new technique in which we did not penetrate the ventral surface of the tongue to reduce the risk of infection and bleeding. The planning-aim dose was 9.5 Gy. The dose that covered 90% of the clinical target volume was 9.6 Gy. The treatment ended without any problems. Acute complications were not observed. The tumor size decreased, and local pain disappeared at post-treatment day 84. No late complications were observed. Two years and 8 months after the treatment, the patient is alive without any obvious recurrence. Additional single-fraction HDR-ISBT boost may be a useful modality as a palliative/symptomatic intent. The implantation technique and dose-fraction schedule may be important for the safe treatment of older patients or those with poor performance status.