Acute radiation dermatitis during head-and-neck radiotherapy: VMAT vs IMPT
Wen-Ling Tsai, Ko-Chun Fang, Yu-Jie Huang, Shang-Yu Chou, Fu-Min FangBackground:
Acute radiation dermatitis (ARD) is common during head-and-neck radiotherapy (RT) and may impair skin-related quality of life (QoL). Whether intensity-modulated proton therapy (IMPT) improves patient-reported skin outcomes compared with volumetric modulated arc therapy (VMAT) remains uncertain. We compared longitudinal outcomes of skin toxicity between RT modalities and identified significant predictors of ARD and skin-related QoL.
Methods:
This prospective and non-randomized cohort study enrolled adults with newly diagnosed head-and-neck cancer receiving curative-intent VMAT or IMPT at Kaohsiung Chang Gung Memorial Hospital. Skin-related QoL was assessed using Skindex-16 at baseline, end of RT, and 3 months after RT. ARD was graded weekly using Common Terminology Criteria for Adverse Events version 5.0. Longitudinal outcomes were analyzed using linear mixed-effects models, and predictors of ARD grade ≥2 and ≥10-point worsening in Skindex-16 Global score were evaluated using multivariable regression.
Results:
Among 158 patients, 113 received VMAT and 45 received IMPT; the mean age was 56.5 years, and 130 patients (82.3%) were men. Clinically meaningful Global score worsening occurred in 37.0% of patients at the end of RT and 7.0% at 3 months after RT. Skindex-16 scores worsened significantly at the end of RT and improved by 3 months across all domains (all p<0.01), with no significant difference between VMAT and IMPT or time-by-modality interactions. Maximum ARD severity was comparable between VMAT and IMPT (grade 2: 30.0% vs 29.5%; grade 3: 7.0% vs 4.8%; p=0.85). Advanced nodal disease (N2–3) and RT dose ≥66 Gy independently predicted ARD grade ≥2 and Skindex-16 Global score worsening.
Conclusion:
Acute patient-reported skin toxicity during contemporary head-and-neck RT was not associated with RT modality but with nodal extent and RT dose. These findings support risk-adapted planning and proactive supportive care, although interpretation is limited by the non-randomized design and lack of skin-specific dosimetry.