Fecal Microbiota Transplantation for Radiation-Induced Proctopathy

Inclusion Criteria: * Age: 18-75 years old * At least 3 months since the completion of pelvic radiotherapy * No evidence of tumor recurrence or metastasis * Rectal bleeding with grade 2-4 by LENT-SOMA scales * Colonoscopy indicating rectal congested mucosa or telangiectasia * Poor response to supportive care, or hemoglobin level less than or equal to 70 g/L in the past 3 months Exclusion Criteria: * Acute or chronic infectious diseases * Serious systemic diseases * Known allergies to any components of the study medication * Colonoscopy indicating rectal ulceration (\>1cm2), fistula, stricture, or necrosis * Late complications related to pelvic radiation injury * Other hemorrhagic or coagulation disorders * Previous rectal resection * Bowel obstruction or perforation that require surgery * Cognitive or psychological disorder * Contraindications to FMT administration