Postoperative high-dose-rate brachytherapy alone in stage T1-3N0M0 oral cancer with negative prognostic factors: A retrospective study

PURPOSE: To evaluate treatment outcomes and toxicity in patients with stage T1-3N0M0 oral cancer treated with surgery followed by high-dose-rate brachytherapy (HDR-BT). METHODS AND MATERIALS: Retrospective study of 50 patients with stage T1-T3N0 tongue and floor-of-mouth cancer who underwent tumour excision (+ elective neck dissection) followed by postoperative HDR-BT due to the presence of negative prognostic factors (close or positive resection margins, lymphovascular and/or perineural invasion, deep invasion). The plastic tube technique (dose: 18 x 3 Gy b.i.d.) was used. Survival outcomes, toxicity, and prognostic factors were evaluated. RESULTS: At a median follow-up of 81 months (range, 4-121), actuarial 5-year local control (LC), nodal control (NC) and progression-free survival (PFS) rates were 79%, 69%, and 64%. After salvage treatment (surgery + external beam radiotherapy), LC, NC, and PFS increased to 87%, 77%, and 72.3%, respectively. Five-year overall survival and cancer-specific survival (CSS) rates were 73% and 77%. Treatmentrelated toxicity included two cases of mandibular osteoradionecrosis and five cases of small soft tissue necrosis. T stage was significantly correlated with nodal control (p = 0.02) and CSS (p = 0.04). Tumour grade correlated with DFS (p = 0.01). CONCLUSION: Postoperative HDR-BT 18 x 3 Gy b.i.d. seems to be an effective method in patients with T1-3N0M0 oral cancer with negative prognostic factors after tumour resection. (c) 2024 American Brachytherapy Society. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.