Technique and outcomes of high-dose-rate interstitial brachytherapy for lip and buccal mucosa cancer: emphasis on cosmetic results

Purpose: High-dose-rate (HDR) brachytherapy is a promising treatment modality for organ and function preservation in lip and oral cavity cancers. This study aims to describe the technique and assess clinical outcomes of HDR interstitial brachytherapy in patients diagnosed with lip and buccal mucosa cancer treated in a comprehensive cancer center. Materials and Methods: We conducted a retrospective analysis of six lip and four buccal mucosa cancer patients with a median age of 69 years (range, 37 to 90) and equal gender distribution, who underwent exclusive interstitial brachytherapy during the study period from May 2019 to December 2024. All procedures were performed under local anesthesia. Most patients were treated with HDR brachytherapy with a total dose of 40 Gy in 10 fractions over 5 days. Patient characteristics, treatment parameters, cosmetic and functional outcomes, and toxicity were assessed. Results: All patients in this cohort achieved local control and remained in remission at the treatment site throughout the follow-up period. The median duration of follow-up was 29 months (range, 16 to 68). Cosmetic outcomes were rated as good in most of the patients. Any acute and late toxicities experienced were manageable; the most severe acute toxicity observed was grade 3, with late toxicity reaching grade 2. Conclusion: Favorable tumor control, good aesthetic results with manageable toxicity, and the minimally invasive approach highlight interstitial brachytherapy as a compelling single treatment modality for eligible patients with lip and buccal mucosa cancer, particularly in older individuals with significant comorbidities.