The Pre-BRA (pre-pectoral Breast Reconstruction EvAluation) feasibility study: protocol for a mixed-methods IDEAL 2a/2b prospective cohort study to determine the safety and effectiveness of prepectoral implant-based breast reconstruction.

Introduction: Implant-based breast reconstruction is the most commonly performed reconstructive technique worldwide. Subpectoral reconstruction with mesh is the current standard of care but new prepectoral techniques have recently been introduced. Prepectoral breast reconstruction (PPBR) may improve outcomes for patients but robust evaluation is required. Randomised clinical trials (RCTs) are ideally needed but the short-term safety of PPBR is yet to be established; the technique and its indications are evolving and it has yet to be adopted by a sufficient number of surgeons for an RCT to be feasible.The Pre-BRA study aims to determine the feasibility of using mixed-methods within an IDEAL 2a/2b (IDEAL, Idea-Development-Exploration-Assessment-Long-term) study to explore the short-term safety of PPBR and determine when the technique is sufficiently stable for evaluation in a pragmatic RCT.

Methods And Analysis: Pre-BRA is an IDEAL stage 2a/2b prospective multicentre cohort study with embedded qualitative research.Consecutive patients electing to undergo immediate PPBR at participating centres will be invited to participate. Demographic, operative, oncology and complication data will be collected and patient-reported outcomes will be assessed at baseline, 3 and 18 months postoperatively. The primary safety endpoint will be implant loss at 3 months.Surgeons performing PPBR will be asked to complete questionnaires regarding their practice and report any modifications made to the procedure or learning arising from complications via free-text response fields on electronic case-report forms. Semistructured will explore surgeons' experiences in detail to identify emerging best practice. This will be fed back to participating surgeons to promote shared learning.The Pre-BRA study will aim to recruit 341 patients from 30 to 40 UK centres over a 12-month period. Recruitment will commence Spring 2019.

Ethics And Dissemination: The study has full ethical approval from OXFORD-B South Central Committee Ref:19/SC/0129. Results will be presented at national and international meetings and published in peer-reviewed journals.

Trial Registration Number: ISRCTN11898000; Pre-results.