We aim to assess the feasibility and acceptability of conducting an RCT to evaluate online delivery of ABC. Results will inform the design, management and future delivery of an evaluation to assess effectiveness and cost-effectiveness in a definitive RCT.

Specific objectives are to:

This is a feasibility study to assess the feasibility and acceptability of the research process and of the ABC programme (online supplemental file 1). To do this, we will use a parallel, two-arm, RCT in which we will monitor participant recruitment and retention, and use qualitative interviews to provide qualitative feedback. Please see figure 1 for the participant pathway through the study.

To be eligible to participate in the study, individuals must fulfil the following inclusion criteria:

Participants will be excluded from participation if they meet any of the following exclusion criteria:

We will recruit n=120 (60 per arm), with participants individually randomised to either the intervention arm (ABC programme plus Macmillan body image booklet) or control arm (Macmillan body image booklet). The objective of this feasibility study is to provide estimates of parameters to inform a subsequent RCT to evaluate intervention effectiveness. Therefore, the study does not need to achieve enough power to detect significant differences, and a formal a priori power calculation is not needed. Rather, the sample size is based on the aim of having a fully powered follow-on substantive or definitive trial, and to help quantify the degree of missing data. Data will be used to estimate the upper one-sided 80% CI for the pooled variance of postintervention self-report outcome measures. For an 80% chance of not being underpowered at any level of power, and for any minimum clinically important difference, a sample of 60 per condition would ensure that the percentage error in estimated sample size for a definitive trial would be no more than 11% (ie, potentially overpowered, but degree of excess restricted to 11%). The estimated sample size for the proposed definitive study can be refined further by estimating the strength of the pre- post-correlation and using these estimates in estimating sample size for repeated measures Analysis of Covariance (ANCOVA)-styled analyses (controlling for commensurate baseline methods), thus resulting in a cost-effective substantive RCT without compromising the reliability of conclusions.

We aim to recruit a diverse group of participants, so we will recruit participants through NHS Participant Identification Centres (PICs), a range of non-NHS organisations (eg, Breast Cancer Now, Maggie’s, Keeping Abreast, Flat Friends, OUTpatients and Black Women Rising) and social media. The PICs will provide study information packs to interested women who have expressed dissatisfaction with their body. The study information pack includes the information sheet and expression of interest form. PICs will also display study posters, which will be used to promote the study through non-NHS organisations and social media. The study posters will include contact details for the study team and signposts to the online information sheet and expression of interest form. Potential participants can contact the study team directly or by completing the online or paper expression of interest form. The study team will then discuss the study with participants over the telephone, ensuring that they understand what is involved in participation and confirming eligibility. Following successful screening, the participant will be sent the online consent form and baseline measures.

Participants recruited through NHS sites will either be approached in person at their standard nurse appointment or via email or post. All other study procedures, including recruitment through non-NHS organisations and social media, screening, consent, data collection and intervention delivery, will be conducted remotely. This remote approach offers a convenient, effective and flexible approach.

Once participants have provided informed consent (online supplemental appendix 1) and completed baseline data collection (T1), they will be randomised to either the intervention or control arm using Sealed Envelope, a web-based randomisation system. Randomisation (at the individual level) will be independent and concealed using permuted block randomisation. Participants will be informed of the result of randomisation via email, along with the Macmillan body image booklet. Participants randomised to take part in the ABC programme will then be booked on to the next suitable group.

The ABC programme comprises seven 2-hour group sessions (with approximately 10 women per group) delivered online weekly via Microsoft Teams. Each ABC group will be delivered jointly by a cancer support specialist (eg, specialist nurse) and psychologist from a Maggie’s centre (Maggie’s is a charity that provides free expert care and support in centres across the UK and online). However, there will be a different pair of facilitators across each group, with some running more than one group (depending on their capacity).

The intervention aims to improve body image among women treated for breast cancer. Rooted in CBT, the ABC programme uses strategies to alter unhelpful thoughts, reduce anxiety and promote non-avoidant behaviours. The programme also explores sociocultural pressures for women, intimacy, physical activity, self-care, mindfulness and relaxation. The sessions are guided using PowerPoint slides and will include individual and group-based activities. Participants are asked to complete readings to prepare for each session and activities to help them to apply the techniques to their day-to-day lives. Table 1 provides an overview of ABC and its content.

Prior to the start of the group, participants will be sent a guide concerning session expectations (eg, format, activities), clear instructions on how to use Microsoft Teams and all intervention materials. Any participants who do not have access to the internet (or have limited data use) will be provided with a data internet card.

Prior to the first ABC session, participants will be asked to read the pre-session intervention materials (ie, Session 1: Part 1) to help them start reflecting on their goals. In the session, there will be introductions and discussion of ground rules before the structured session content is delivered. All participants will be asked to have the second part of the intervention materials for the session (ie, Session 1: Part 2) in front of them to facilitate individual and group exercises. At the end, they will also be asked to complete two between-session activities at home (eg, mirror exposure exercise) before the next session. They will also be advised to read the pre-session intervention materials (ie, Session 2: Part 1) for the following week’s session. The same format then continues for all sessions.

All facilitators will have experience of running support groups for those who have had cancer and experience of working specifically with women who have had breast cancer. Facilitators will receive 1 day of online training from the first author and will be provided with all the relevant materials. Facilitators will receive ongoing supervision from the first author and will provide feedback on the programme.

There is no current ‘treatment-as-usual’ in relation to body image support for women treated for breast cancer; however, Macmillan have produced a body image booklet for people who have had cancer which is currently freely available. This booklet provides a substantial amount of support and guidance relating to managing body image concerns. It explains the effects of cancer on body image and provides practical guidance (eg, make-up) and psychoeducational guidance (eg, managing others’ reactions), in addition to some CBT strategies. The Macmillan booklet is therefore a suitable source of information and support for participants in the control arm, who will be sent the booklet and encouraged to work through it gradually when informed of their allocation to the control arm.

Intervention fidelity will be assessed across different ABC groups and sessions. All ABC sessions will be recorded, with 50% then assessed by the research team for the perceived competency (percentage reflecting how well facilitators delivered the sessions) and intervention adherence (percentage reflecting the extent to which facilitators completed each section of the sessions).

Qualtrics will be used to manage consent and data collection throughout the study. Data will be protected via a password and backed up automatically. Data will be exported to SPSS for data cleaning and analysis. We will regularly check data to ensure high data quality.

Data will be collected at four timepoints: baseline (T1), 9 weeks post baseline (T2; immediate post intervention) 20 weeks post baseline (T3) and 32 weeks post baseline (T4). See table 2 for a detailed breakdown of the schedule of assessments.

The feasibility and acceptability of the ABC programme and the research process will be quantitatively assessed through descriptive statistical analyses of monitoring data and self-report rating scales. We will report data in line with the Consolidated Standards of Reporting Trials 2010 Statement showing attrition rates and loss to follow-up. In addition, feasibility and acceptability will be qualitatively assessed using ‘codebook’ thematic analysis of open-ended questions and interviews, whereby text will be coded using a priori codes and themes relating to feasibility and acceptability.40

The self-report outcome measures (K10, BAS-2, FACT-B: Breast Cancer Subscale, Hopwood Body Image Scale and BREAST-Q: Sexual Well-Being Scale) are each well-established validated measures which will be scored according to the most appropriate guidelines. The design (pre- post- two-arm parallel RCT) and the selected measures are amenable to analysis using long-established statistical techniques. The analysis will proceed using the intention-to-treat analysis set with the statistician blinded to allocation. These analyses include

• Adjusted statistical comparison between arms at each timepoint (T2, T3, T4) will be conducted controlling for commensurate baseline measures using ANCOVA, along with 95% and 80% covariate-adjusted CIs and quantification of effect size using partial η². If statistical assumptions do not seem tenable, robust remedies will be considered, including a baseline by randomised arm interaction effect, or homoscedasticity-corrected robust standard errors (HC3) or the robust non-parametric bootstrap equivalent ANCOVA.

The draft ABC AD-SUS will undergo testing for the following:

• Acceptability: this will be assessed via the proportion of participants completing the measure, percentage of missing items and consideration of the clarity of any questions associated with missing data.

• Comprehensiveness: this will be assessed via open-ended questions included in the AD-SUS asking participants to report any ‘other’ services not reported elsewhere in the measure (missing items).

• Redundancy: this will be assessed through consideration of any service items included in the AD-SUS but not reported as being used by any participant (redundant items).

These results, plus feedback from participants, will inform a final version of the AD-SUS for a future definitive trial.

Acceptability of the EQ-5D-5L, ReQoL-10 and WSAS will be assessed using completion rates (proportion of participants completing each of the measures and percentage of missing items within each of the measures), plus feedback from participants. Service use, health-related quality of life and the WSAS will be summarised and reported descriptively.

The study has benefited from substantial PPIE. This has included a PPIE lead and coapplicant who had extensive involvement in the design of the study. In addition to the PPIE lead, there has been PPIE involvement throughout every stage of the development of ABC and its preliminary evaluation. Women treated for breast cancer, associated health professionals (eg, cancer nurse specialists, psychologists) and cancer support organisations (eg, Breast Cancer Now) contributed to the adaptation of the original intervention and its acceptability testing. A study public advisory group comprising a diverse group of women who had been treated for breast cancer have informed several aspects of the study including the research protocol, participant-facing research materials and the ABC programme materials. Along with the PPIE lead, this public advisory group will continue to advise the study team through the analysis and dissemination stages.

Independent oversight and supervision of the study will be provided by the trial steering committee. The steering committee will meet twice a year to monitor the progress and conduct of the study, and where relevant provide clinical and professional advice relating to the study. The steering committee will comprise a professor in long-term conditions, lived experience representatives, a professor of psychosocial oncology, a clinical psychologist and service lead for a cancer support centre, an associate director of services for a national cancer organisation and a chief nursing officer for a national cancer organisation.

Not applicable.