Patient experience of head and neck treatment on a 1.5 T MR-Linac: is the ATS-lite adaptive solution tolerable?

Introduction: Head and neck cancer (HNC) treatment on the Unity MR-Linac (MRL) (Elekta AB, Stockholm, Sweden) has been developed using the novel adapt-to-shape Lite (ATS-lite) method to create clinically acceptable adaptive treatments clinician-free. Here we investigate patient experience and acceptability of this technique. Methods: Ten HNC patients treated to 65 Gy in 30 fractions with MRI-guided adaptive radiotherapy (MRIgART) within the PERMIT trial (NCT03727698), were included. Data collected comprised patient demographics, treatment time, and patient experience, using an established MRL questionnaire.Back-up plans were created for use on the conventional linac with CT guidance, to prevent missed fractions. The frequency of use was collected and categorised to reflect the cause. Results: The median total treatment time for ATS-lite method was 39 min. The percentage of treatments under 60 mins was 98.8 %.Questionnaire response rate was 85% and individual question response rate was 99%. Ninety-six percent of responses scored 2 or 3 on the Likert scale, a positive answer. The lowest scoring question was "I forced myself to manage the situation," with a mean (SD) of 2.4 (0.9).The MRL delivered 84.7 % of treatments. The back-up plan was used for 46 fractions, 7 attributed to patient tolerance (n = 2 patients). Conclusion: Average treatment times for the ATS-lite HNC MRIgART are acceptable and faster than reported ATP treatment times. Patient-reported experience was extremely positive. Use of back-up plans attributable to lack of patient tolerance was low. This technique can used with the confidence that patient experience is not negatively impacted.