Transanal irrigation for the management of low anterior resection syndrome (LARS): protocol for a pragmatic, multicentre, crossover randomised controlled trial.

introductionAdvances in surgical techniques and neoadjuvant care for rectal cancer have increased sphincter preservation, allowing restoration of bowel continuity through low anterior resection (LAR). However, up to 75% of patients experience low anterior resection syndrome (LARS), which is bowel dysfunction characterised by faecal incontinence, frequency, urgency and clustering of bowel movements, significantly impairing quality of life (QoL). Current management is largely empirical, using lifestyle or pharmacological strategies with variable success. Transanal irrigation (TAI) is a non-surgical intervention that allows controlled colonic washouts, improving symptom control. Evidence supporting TAI for LARS is limited by small sample sizes and is primarily observational, highlighting the need for a rigorous randomised controlled trial (RCT). This study aims to compare TAI with conventional LARS care on QoL, bowel function, faecal incontinence and satisfaction in adults with LARS following LAR. METHODS AND ANALYSIS: This is a pragmatic, multicentre, crossover RCT conducted at eight academic hospitals across Quebec, Ontario and British Columbia, Canada. Eligible participants are adults (≥18 years) with an LARS score >20, at least 6 months post-LAR and without an ostomy or active colorectal complications. Participants will be randomised to receive either 3 months of daily TAI or conventional LARS care, followed by a 1 month washout and crossover to the alternate intervention. The TAI intervention includes an irrigation system, access to a web-based educational platform and virtual training with a research team member. Primary outcome is difference in global QoL between interventions, assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30. Secondary outcomes include bowel function (LARS score), faecal incontinence (Cleveland Clinic Faecal Incontinence Score) and satisfaction. Sample size (n=66, accounting for 10% attrition) was determined using Monte Carlo simulations to detect a 6-point difference in QoL with 85.8% power. Data will be analysed using linear mixed-effects models accounting for period, treatment and sequence effects. All study data will be collected via Research Electronic Data Capture and maintained in secure, password-protected systems; participant confidentiality will be ensured throughout. Safety monitoring will include training on proper TAI technique and reporting of adverse events. ETHICS AND DISSEMINATION: The study has received ethics approval from each participating site. The trial adheres to the Canadian Tri-Council Policy Statement on the use of human participants in research. Findings will be disseminated through peer-reviewed journals, conference presentations and scientific meetings, with authorship following the International Committee of Journal Editors guidelines. TRIAL REGISTRATION NUMBER: NCT05007015.