Development of a risk prediction tool for patients with locally advanced and recurrent rectal cancer undergoing pelvic exenteration: protocol for a mixed-methods study

Introduction Pelvic exenteration (PE) surgery represents the only potentially curative treatment option for patients with locally advanced or recurrent rectal cancer (LARRC). Given the potential morbidity, whether or not PE should be recommended for an individual patient presents a major decisional conflict. This study aims to identify the outcomes of PE for which there is consensus among patients, carers and clinicians regarding their importance in guiding treatment decision-making, and to develop a risk prediction tool which predicts these outcomes.Methods and analysis This study will be conducted at a specialist PE centre, and employ a mixed-methods study design, divided into three distinct phases. In phase 1, outcomes of PE will be identified through a comprehensive systematic review of the literature (phase 1a), followed by exploration of the experiences of individuals who have undergone PE for LARRC and their carers (phase 1b, target sample size 10-20 patients and 5-10 carers). In phase 2, a survey of patients, their carers and clinicians will be conducted using Delphi methodology to explore consensus around the outcomes of highest priority and the level of influence each outcome should have on treatment decision-making. In phase 3 a, risk prediction tool will be developed using data from a single PE referral centre (estimated sample size 500 patients) to predict priority outcomes using multivariate modelling, and externally validated using data from an international PE collaboration.Ethics and dissemination Ethical approval has been granted for phases 1 and 2 (X22-0422 and 2022/ETH02659) and for maintenance of the database used in phase 3 (X13-0283 and HREC/13/RPAH/504). Informed consent will be obtained from participants in phases 1b and 2; a waiver of consent for secondary use of data in phase 3 will be sought. Study results will be submitted for publication in international and/or national peer reviewed journals.PROSPERO registration number CRD42022351909.