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.