Abstract P6-12-04: Does the addition of a patient decision aid video reduce decisional conflict in patients considering a de-escalation of radiotherapy trial? Results from the PRIMETIME study
Authors: Bhattacharya Indrani Subarna , Haviland Joanne , Balasopoulou Ada , Stones Liba , Stobart Hilary , Turner Lesley , Hopwood Penelope , Coles Charlotte E , Bliss Judith M 
Published: March 2020

Abstract
Background: PRIMETIME is a UK-led prospective biomarker-directed cohort study aiming to identify a group of breast cancer patients who can safely avoid radiotherapy following breast conserving surgery. This group is deemed to be at such a low risk of local relapse that the potential benefits of radiotherapy are unlikely to outweigh the risks. The uncertainty patients face regarding healthcare decisions is known as decisional conflict. Patient decision aids (PDA) are interventions which help patients to weigh up the risks and benefits of treatments. Evidence suggests PDA reduce decisional conflict. A study within a trial (SWAT) concept which enables trialists to conduct research embedded within a larger trial was used to investigate if the introduction of a PDA video reduces decisional conflict within PRIMETIME.
Methods: The PDA video was designed to be used in addition to the standard written information and developed in close collaboration with PRIMETIME patient advocates. The PRIMETIME SWAT was implemented using a cluster stepped-wedge trial design. Each cluster was defined as the radiotherapy centre and peripheral centres referring into that centre. All clusters began in the standard information group (receiving written information) and then crossed over to the enhanced information group (receiving written information and PDA video) at either 2, 4 or 6 months. The primary endpoint was a reduction in decisional conflict following PDA implementation. Decisional conflict was assessed using the validated decisional conflict scale questionnaire (0-100 scale with greater scores indicating more decisional conflict) in the standard and enhanced information groups. The target sample size was 288 patients from 24 clusters, to provide 84% power (alpha 0.05) with an effect size of 0.55 (assuming standard deviation, SD=18) across the 0-1 range of possible intra-class correlation values. For the primary endpoint an estimate of the difference in mean decisional conflict pre- and post-implementation of the PDA video was obtained from a multilevel mixed effects linear regression model.
Results: In an interim analysis conducted on 2nd May 2019, 318 evaluable questionnaires were returned from 463 eligible patients (69%) recruited across 24 clusters; 158 questionnaires from the standard and 160 questionnaires from the enhanced group. 60/130 (53%) patients in the enhanced information group (with available data) reportedly did not watch the PDA video.
The mean decisional conflict score in the standard group [158 patients] was 10.73 (SD=11.63) and 8.43 (10.83) in the enhanced group [160 patients]. There was a reduction in decisional conflict in the enhanced compared with the standard group, however the effect size was small and unlikely to be clinically significant [estimated difference in means = -2.50 (-4.73- -0.28), p=0.03, effect size=0.11]. The final analysis will be conducted after the last cluster has crossed over to the enhanced group in October 2019.
Conclusions: A SWAT using a cluster stepped-wedge trial design testing the implementation of a PDA video on patient’s decisional conflict was conducted across multiple UK centres participating in PRIMETIME. The average decisional conflict scores were low therefore there is less scope for obtaining further reductions, and the difference we observed was not clinically significant. The low baseline scores may reflect the PRIMETIME study population who are at low risk of local recurrence. Almost half of patients reportedly did not watch the video; this may be due to the standard written information being sufficient to fulfil the needs of this patient population.
Citation Format: Indrani Subarna Bhattacharya, Joanne Haviland, Ada Balasopoulou, Liba Stones, Hilary Stobart, Lesley Turner, Penelope Hopwood, Charlotte E Coles, Judith M Bliss. Does the addition of a patient decision aid video reduce decisional conflict in patients considering a de-escalation of radiotherapy trial? Results from the PRIMETIME study [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-12-04.