Evaluation of the Local Control Rate and Late Toxicity of High-Dose-Rate Interstitial Brachytherapy in Tongue Squamous Cell Carcinoma.

Background: Tongue Squamous Cell Carcinoma (TSCC) is one of the most consequential oral Squamous Cell Carcinomas (SCC) worldwide. Methods: This retrospective cross-sectional study was conducted on 29 TSCC patients treated with High Dose Rate Brachytherapy (HDR-BT) with or without External Beam Radiotherapy (EBRT) between 2017-2020. Patients without distant metastasis at the time of treatment and at least one year after completion of brachytherapy were included. Results: One-year Overall Survival (OS), Disease-Free Survival (DFS), and Local Control Rate (LCR) were 82.8, 79.3, and 100%, respectively. 6 patients (20.7%) had distant metastasis, of which 5 (17.2%) died. Local recurrence was not observed in any patients, and only one (3.4%) regional recurrence occurred. The most common late toxicity of HDR-BT was dry mouth (79.2%) and dysarthria (66.7%). There were no severe and life-threatening complications (grades 3 and 4) during one year. Also, 79.2% of the patients had good functional performance. One-year OS, the significant difference between the two groups of HDR-BT with and without EBRT (p=0.055). Conclusion: Our findings indicated that the HDR-BT increases the OS of TSCC patients more than EBRT without developing grade 3-4 AEs and metastasis. We showed that the mean 3.2 ±0.7 Gy of HDR-BT has more OS compared to EBRT. [ABSTRACT FROM AUTHOR]