Feasibility of Predicting Incidental Gallbladder Cancer: a protocol for a UK multicentre feasibility diagnostic modelling study for incidental gallbladder cancer in adult cholecystectomy

Abstract Background: In the UK, gallbladder specimens are routinely sent for histological examination to exclude incidental gallbladder cancer (iGBC) and other clinically relevant pathology. Although rare, gallbladder cancer requires early detection to improve outcomes. Existing risk stratification tools miss cases or are not tailored to the UK population. Predicting Incidental Gallbladder Cancer (P-iGBC) is an adaptive, multicentre, cross-sectional, trainee-led collaborative study designed to develop a diagnostic score to stratify iGBC risk in adult cholecystectomy. This feasibility phase, fP-iGBC, evaluates the methods and procedures of the overall study, ensuring its robustness and practicality before full-scale implementation. Methods: fP-iGBC comprises an internal pilot of P-iGBC with a parallel qualitative study. The internal pilot investigates recruitment, data collection and study procedures in adults undergoing cholecystectomy for benign disease. The qualitative study explores attitudes of patients and professionals towards iGBC risk and selective histological analysis. Outcomes: The primary objectives were to evaluate screening processes, recruitment and data completeness. Additionally, the incidence of clinically relevant histological abnormalities will be compared against published evidence. A collaborator survey will identify challenges in study procedures. The qualitative study will explore the study’s value. Interim analysis will assess screening and recruitment targets against predefined progression criteria. Ethics and Registration: P-iGBC is approved by the London-Central National Health Service Research Ethics Committee (24/LO/0504), the University of Plymouth Faculty Research Ethics and Integrity Committee (PEOS 5550) and is registered at ClinicalTrials.gov (NCT06531408). Conclusion: fP-iGBC will assess the feasibility of P-iGBC and inform necessary protocol amendments to ensure successful implementation of subsequent research phases.