Digital Body Mindset Intervention for Young Cancer Survivors

The Young Adult Pediatric Quality of Life Inventory 4.0 Generic Core Scale (PedsQL) measure assesses four domains of HRQOL using 23 items across separate subscales of physical, social, emotional and school functioning. For all items, individuals respond on a 5-point likert scale with an amended 7 day recall period (0= never a problem, 4= almost always a problem). Higher PedsQL 4.0 scores indicate better HRQOL.

The Body Mindset Inventory (BMI-2) contains items that assess different mindsets about the body, capturing both adaptive and maladaptive mindsets. For all items, individuals respond on a 6-point Likert scale (6= strongly agree, 1= strongly disagree). Higher mean scores on each mindset subscale indicate greater endorsement of that mindset.

The Illness Mindset Inventory (IMI) contains 9 items that assess different mindsets about the body and about cancer, capturing both adaptive ('manageable', 'opportunity') and maladaptive ('catastrophe') mindsets. For all items, individuals respond on a 6-point Likert scale (6= strongly agree, 1= strongly disagree). Higher mean scores on each mindset subscale indicate greater endorsement of that mindset.

The Functionality Appreciation Scale (FAS) (Alleva et al, 2017) contains 7-items that capture the overall appreciation of the body's ability to function to the extent that it can. Individuals respond to items on a 5-point Likert scale (1=strongly disagree, to 5=strongly agree). A total score is created by summing items where higher scores reflect a higher appreciation for the functionality of the body.

Items from the The Graded Chronic Pain Scale-Revised (Von Korff et al., 2020) and the body map from the Brief Pain Inventory (Cleeland et al, 1994) will be used to assess pain, including pain interference.

The Hospital Anxiety and Depression Scale (HADS) contains 14-items assessing anxiety and depression symptoms with two separate subscales, each consisting of seven items. Items are rated from 0 to 3 and subscale scores range from 0 (no distress) to 21 (maximum distress).

The Fear of Cancer Recurrence Inventory Short Form (FCRI-SF) contains 9-items assessing presence, frequency, intensity, and duration of fear of cancer recurrence thoughts and individual perceived risk of cancer recurrence. Items are rated on a 5-point likert scale and are amended to a 7 day recall period (0= not at all, 4= a great deal). Item five is reverse scored and total scores range from 0 to 36; higher scores reflect greater fear of cancer recurrence.

The Post-Traumatic Growth Inventory contains 21-items that evaluates positive changes after experiencing a stressful event such as cancer. Individuals respond on a 6-point Likert scale (0= I have not experienced this change as a result of my cancer experience - 6= I have experienced this change to a very great degree as a result of my cancer experience). A total score is created by summing all items. The scale also contains five factors and therefore separate scores can be created for each of these factors (relating to others, new possibilities, personal strength, spiritual change, appreciation of life).

The Bodily Threat Monitoring Scale (Heathcote et al, 2023) captures tendencies to monitor and appraise bodily sensations as symptomatic of something being wrong with one's body. The original scale includes 19-items, however a Short Form was used for this study. Each item is rated on a 5-point Likert scale (0= not at all like me, 4= entirely like me). Scores from items are summed and higher scores represent greater bodily threat monitoring.

Physical activity will be captured using the Godin Leisure-Time Exercise Questionnaire (GLTEQ), which assesses physical activity throughout an individual's week based on four levels of activity intensity: strenuous, moderate, mild and sedentary. Higher scores indicate higher leisure-time physical activity.

The PedsQL multidimensional fatigue scale captures general fatigue, sleep/rest fatigue and cognitive fatigue. This study uses the General Fatigue subscale. Respondents rate each of the 6 items on the General subscale a 5-point Likert scale ranging from 0 (never a problem) to 4 (almost always a problem). Scores are summed and higher scores indicate greater general levels of fatigue.

The Global Impression of Change (GIC) contains one item will be used to evaluate a patient's overall perception of improvement or deterioration over time from taking part in the EMBody study.

Nine items adapted from the Net Promoter Scale will capture acceptability of the EMBody intervention. Two additional open ended questions will also enable participants to provide written feedback on the intervention.

Wileman et al 2024's adverse events and risk assessment protocol for digital trials has been amended to capture adverse events. Questions designed to capture adverse events (physical, psychological or otherwise) and suicidal ideation intent will be asked based on Wileman's 2024 protocol using the PHQ9 and an additional question asking about plan for those reporting intent. Participants will also have access to an open field text response prompting them to share any details of possible side effects or events related to their duration of taking part in the study. This will be accessible to participants 24/7 to capture further information about possible adverse events.

The HRV4Training app (www.hrv4training.com) will be used to capture 1 minute measurements of heart rate variability (HRV) using a mobile device camera while seated.

The UK Cancer Costs Questionnaire assess the financial impact of cancer on patients and their families. Costs from usage across services can be summed to indicate financial burden and cost associated with healthcare usage. Three additional items will be provided at T3 to the intervention group to capture whether participants have sought psychological support since receiving the intervention.

Four items have been developed to capture the impact of intervention delivery through hearing stories from relatable others. Individuals respond on a 5-point likert scale from strongly disagree to strongly agree, and scores across items are summed to create a total score. Items will be provided for the intervention group only.

Participants in the intervention arm will be invited to take part in an optional semi-structured interview to provide qualitative feedback on the EMBody intervention.