ESTRO 2025 - Abstract Book

S4434

Late-breaking abstracts

ESTRO 2025

Results

141 patients were randomised between January 2024 to January 2025 into three arms: 55 received closed ‐ face masks (Arm-A), 47 three ‐ point open ‐ face masks (Arm-B), and 39 five ‐ point open ‐ face masks (Arm-C). Analysis of translational and rotational dimensions found no statistically significant differences among the three arms, except in the long dimension, where Arm-A was significantly larger than either open ‐ face group(Figure2). Specifically, Arm-A vs. Arm-B was 1.33±1.14mm vs. −0.11±1.16mm (p<0.001), and Arm-A vs. Arm-C was 1.33±1.14mm vs. −0.33 ± 1.06mm (p<0.001). This difference did not translate into differing PTV margins between arms in the long dimension. SGRT confirmed no increase in intrafraction motion with open ‐ face masks, along with improved long setup accuracy compared to closed ‐ face masks. At treatment completion, overall experience for patients with both open masks was significantly more favourable than closed masks (Arm-A vs Arm-B p=0.001, Arm- A vs Arm-C p=0.004). 3-point open had significantly better comfort, tolerability and overall experience scores compared to closed-masks at both the beginning (comfort p=0.4, tolerability p=0.02, overall p=0.02) and end of treatment (comfort p=0.02, tolerability p=0.001, overall p=0.001). The replanning rate was 38% lower in the 3 point open vs closed arm. Conclusion These are the first reported results of a fully open 3-point mask in a randomised trial, demonstrating improved patient experience, equivalent setup accuracy and reduced replanning rates supporting a new standard of care. References 1 Forbes, et al.'Having the mask on didn't worry me until they clamped my head down so I wouldn't move':A qualitative study exploring anxiety in patients with head and neck cancer during radiation therapy.JMedRadiatSci.2023Sep;70(3):283-291. 2 Mulla,et al.comparative study between open-face and closed face-masks for head and neck cancer.ReppractOncolRadiother.May-June2020,25,3:382-388. 3 Wiant, et al. A prospective evaluation of open face masks for head and neck radiation therapy. PractRadiatOncol.2016Nov-Dec6,259-267. 4 Lee,et al.The immobilization performance of a novel “open face” mask used for the set-up of claustrophobic patients being treated for Head-and-Neck cancers.InternationalJournalofRadiation Oncology,Biology,Physics2012 84(3) Keywords: Head and neck, open masks, sgrt