Dosimetrical Correlation between Cervical Site Radiation Dose and Radiation Dermatitis in Advanced Nasopharyngeal Carcinoma: A Retrospective Analysis

Introduction To investigate the dosimetric correlation between radiation dose to the cervical site and radiation-induced dermatitis in patients with advanced nasopharyngeal carcinoma undergoing concurrent chemoradiotherapy. Methods Data from 109 patients treated with concurrent chemoradiotherapy between November 2018 and June 2020 were analyzed. The study focuses on identifying clinical and dosimetric factors associated with moderate to severe radiation dermatitis and determining the optimal radiation dose to the cervical site. Results Univariate analysis revealed that nodal stage, tumor node metastasis stage, volume to gross tumor volume of the neck, and mean dose to the cervical site were associated with an increased risk of grade 3/4 radiation dermatitis. Multivariate analysis identified cervical site of mean dose (odds ratio=1.003; 95%confidence Interval=1.001-1.005; P =0.003) as an independent predictor. The optimal cut-off value of cervical site as was 5206 centigray (area under curve =0.733%; P <0.01;95% confidence Interval =0.637-0.829). Discussions While prior studies have established an association between cervical radiation dose and dermatitis severity, detailed radiotherapy dose-specific data regarding radiation dermatitis remain scarce. This study aims to clarify in detail the toxicity levels of such skin damage across different radiation doses and provides precise dosimetric insights. Conclusion Moderate or severe radiation dermatitis is significantly correlated with the mean dose to the cervical site, and keeping the cervical dose below 5200 centigray may decrease the incidence of severe skin toxicity. We recommend patients with mean dose over 5200 centigray to consider topical treatment during the early stages of radiotherapy and advanced techniques to reduce radiation volumes and doses to the cervical site may be useful.