Protocol for a mixed-method study to inform the feasibility of undertaking a large-scale multicentre study comparing the clinical and patient-reported outcomes of oncoplastic breast conservation as an alternative to mastectomy with or without immediate breast reconstruction in women unsuitable for standard breast-conserving surgery (the ANTHEM Feasibility Study)

Introduction: Approximately 40% of the 55,000 women diagnosed with breast cancer each year in the UK undergo mastectomy because they are considered unsuitable for standard breast conserving surgery (BCS) due to tumour size or multiple tumour foci. Mastectomy can significantly impact women’s quality of life and only 1 in 4 women currently undergo immediate breast reconstruction (IBR). Level 2 oncoplastic breast conserving surgery (OPBCS) that combine removing the cancer with a range of plastic surgical volume replacement (e.g. local perforator flaps) and volume displacement techniques (e.g. therapeutic mammaplasty) that can extend the role of BCS and may allow some women not suitable for standard BCS to avoid mastectomy. High-quality research to determine whether OPBCS offers a safe and effective alternative to mastectomy +/- IBR is currently lacking. Preliminary work is needed to ensure a future large-scale study is feasible, well-designed and addresses questions important to patients and the NHS. Methods and analysis: Mixed methods will be used to inform feasibility and design of a future large-scale study comparing the clinical and cost-effectiveness of OPBCS and mastectomy +/- IBR. It will have four parts: 1. A national practice questionnaire to determine current practice and provision of oncoplastic breast and reconstructive surgery in the UK 2. A pilot multicentre prospective cohort study to explore the proportion of patients choosing OPBCS vs. mastectomy; the proportion in whom OPBCS is successful and clinical and patient-reported outcomes of different techniques at 3 and 12-months post-surgery. 3. A qualitative interview study to explore patients’ attitudes to different procedures; rationale for decision-making and perceptions of outcomes. 4. Design of the future study All centres offering OPBCS and mastectomy in the UK will be invited to participate. Recruitment is planned to commence winter 2020 and continue for 12 months. Ethics and dissemination: The study has ethical approval from the Wales REC 6 National Research Ethics Service (REC Ref 20/WA/0225). Results will be presented at national and international meetings and published in peer-reviewed journals. We will work with patients to develop lay summaries and share these through patient groups and breast cancer charities. Trial registration number: ISRCTN18238549 STRENGTHS AND LIMITATIONS OF THIS STUDY • This mixed methods study will determine whether it is possible to undertake a large prospective cohort study directly comparing the clinical and cost-effectiveness of oncoplastic breast conserving surgery and mastectomy with or without breast reconstruction in patients considered suitable for both procedures. • It will determine whether the BREAST-Q core breast cancer modules are an appropriate and meaningful patient-reported outcome measure for use in a future comparative study. • Qualitative interviews will explore patients’ attitudes to different procedures, rationale for decision making and perception of outcomes providing the opportunity to improve informed consent in this group. • Suitability for OPBCS will be assessed by individual surgeons or teams. It is multifactorial with subjective elements and is likely to vary between individuals and centres. • Patients will only be followed up for 12 months and the effects of radiotherapy and any revisional surgery are likely to occur at a later time point.