Autologous Fecal Microbiota Transplantation for Diversion Colitis

Diversion colitis (DC) is a common inflammatory complication in patients with temporary ileostomy after rectal cancer surgery, and no standardized medical treatment exists. This prospective, assessor-blinded, parallel-group, randomized controlled trial evaluated whether autologous fecal microbiota transplantation (auto-FMT) delivered through the diverting stoma ameliorates DC and improves post-reversal outcomes. Sixty-six patients with endoscopically confirmed DC were randomized 1:1 to receive daily auto-FMT (n=33) or saline irrigation (n=33) for four weeks. The primary endpoints are changes from baseline to week 4 in endoscopic (modified Harig score, 0-12) and histopathological (0-9) scores. Secondary endpoints include Wexner incontinence score, quality of life (EORTC QLQ-C30/CR29), inflammatory biomarkers, and safety. The study is designed to test whether auto-FMT produces superior improvements in endoscopic and histopathological severity compared with saline control, and leads to better functional outcomes after stoma reversal.

Inclusion Criteria: * Histopathologically confirmed rectal adenocarcinoma. * Low anterior resection with temporary loop ileostomy. * Age 18-75 years. * Scheduled for ileostomy reversal at 3-6 months after primary surgery. * Endoscopic confirmation of diversion colitis at week 4 post-ileostomy (modified Harig score ≥4, range 0-12). * Written informed consent. Exclusion Criteria: * Neoadjuvant chemoradiotherapy. * Pre-existing inflammatory bowel disease, irritable bowel syndrome, or chronic constipation. * Previous colorectal surgery (other than index surgery). * Active infection requiring systemic antibiotics within 4 weeks before enrollment. * Use of probiotics, prebiotics, or antibiotics within 4 weeks before enrollment. * Severe organ dysfunction (Child-Pugh B/C cirrhosis, end-stage renal disease). * Pregnancy or lactation. * Any condition precluding protocol compliance or outcome assessment.