KEY POINTS
- The phase 3 OPEN trial randomized 230 non-claustrophobic patients receiving radical head and neck RT to a conventional closed 5-point mask without SGRT, a 3-point open mask with SGRT, or a 5-point open mask with SGRT.
- The primary setup analysis included 199 patients: 68 with closed masks, 71 with 3-point open masks, and 60 with 5-point open masks. All patients underwent CBCT-based positioning.
- Setup accuracy was comparable across the three approaches in vertical, lateral, and rotational dimensions. The only significant difference favored open masks: the closed-mask group had larger longitudinal interfraction shifts (p<0.001).
- Psychological distress favored the open-mask approaches. At treatment completion, the proportion with GHQ-12 scores above the distress threshold was 44.3% with closed masks, 32.9% with 3-point open masks, and 18.0% with 5-point open masks.
- Patient-reported overall experience was significantly better with both open masks versus the closed mask (p<0.001 for 3-point; p<0.004 for 5-point). The 3-point open mask also produced significantly better tolerability scores at treatment completion.
- Open-mask workflows did not meaningfully increase resource use. Median treatment time remained <15 minutes, and the average number of CBCTs per patient was 1.2 across all arms.
- Eighteen mask-related replans occurred among 230 patients: 9 closed, 6 three-point open, and 3 five-point open. Notably, 6/82 patients initially assigned closed masks required conversion to open masks because of intolerance, despite claustrophobic patients being excluded from enrolment.
CLINICAL TAKEAWAY
For centres with a validated SGRT workflow, open-face immobilization can improve the head and neck RT experience without sacrificing setup reproducibility. This is unusually strong evidence for a practical workflow change, although the study excluded patients with known claustrophobia and was performed within an experienced SGRT network.