KANGFUPEN Liquid Dressing for Chronic Radiation-Induced Rectal Injury

Inclusion Criteria: * Fully voluntary with decision-making capacity * 18-80 years old * Completed pelvic radiotherapy for malignancy ≥3 months prior * Evidence of chronic radiation-induced rectal injury (RTOG Grade ≥2) * Evidence of radiation-induced rectal injury on colonoscopy (within 3 months, Vienna endoscopic score ≥1) * No prior surgery * ECOG score 0-2 * Estimated survival ≥1 year Exclusion Criteria: * Primary rectal tumours or pelvic malignancies with rectal involvement * Uncontrolled, recurrent, or metastatic tumours * Concurrent anticancer therapies including radiotherapy, chemotherapy, targeted therapy, immunotherapy and traditional Chinese medicine with anti-tumour properties * Patients with intestinal fistula, perforation, or obstruction * History of electrocautery treatment within 1 month * Recent medication use (within 2 weeks): traditional Chinese medicine enemas, mesalazine (oral or rectal) and other anti-inflammatory bowel medications * History of superoxide dismutase allergy * Pre-existing chronic colitis, ulcerative colitis, or nonspecific proctitis * Connective tissue diseases requiring long-term corticosteroid therapy * Pregnant or lactating women * Active infection or fever * Other severe comorbidities potentially affecting trial compliance: unstable cardiac disease requiring treatment, renal disorders, chronic hepatitis, poorly controlled diabetes and psychiatric illnesses