Autologous Fecal Microbiota Transplantation for Anal Function Recovery After Ileostomy Reversal in Rectal Cancer

This prospective, single-center, single-arm, open-label clinical study aims to evaluate whether autologous fecal microbiota transplantation can improve bowel and anal function after ileostomy reversal in patients with rectal cancer who underwent radical rectal cancer surgery with protective loop ileostomy. Eligible patients will receive autologous fecal microbiota transplantation before ileostomy reversal. The primary outcome is the Low Anterior Resection Syndrome score at 3 months after ileostomy reversal. Secondary outcomes include fecal incontinence score, colonoscopic findings before ileostomy reversal, gut microbiota profiles, inflammatory markers, anorectal manometry, pelvic floor electromyography, and safety outcomes.

Inclusion Criteria: 1. Age 18 to 75 years. 2. Histologically or clinically confirmed rectal cancer with the lower tumor margin less than 12 cm from the anal verge. 3. Undergoing radical rectal cancer surgery with protective loop ileostomy. 4. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. 5. Able to understand the study procedures and willing to provide written informed consent. Exclusion Criteria: 1. History of inflammatory bowel disease, bacterial colitis, or other preoperative colonic inflammatory disease. 2. Requirement for emergency surgery due to intestinal obstruction, perforation, bleeding, or other emergency conditions. 3. Pregnant or lactating women. 4. Presence of clinically significant gut microbiota dysbiosis before enrollment, as judged by the investigator. 5. Planned postoperative radiotherapy, chemotherapy, or chemoradiotherapy. 6. Poor compliance, inability to tolerate the intervention, or judged by the investigator to be unsuitable for participation in this clinical study. 7. Severe postoperative complications such as anastomotic leakage.