This is a randomized controlled trial to explore the exploring the non-inferiority of CMTS0515-augmented WMT compared to WMT.

At least 60 subjects who meet all the inclusion criteria but do not meet any exclusion criteria will be enrolled in this study. They will be randomly assigned to the experimental group (CMTS0515-augmented WMT) and the control group (WMT). Data of demographic characteristics, intestinal symptoms, medicine treatment usage and clinical outcomes will be collected. After treatment, they will enter the follow-up period for efficacy and safety evaluation.

Inclusion Criteria:

1. Histopathologically confirmed diagnosis of abdominal or pelvic cancer;
2. Completion of at least one entire course of radiation therapy;
3. Age ≥18 years at the time of cancer diagnosis.

Exclusion Criteria:

1. Absence of intestinal symptoms or transient intestinal symptoms;
2. Radiation treatment involving areas outside the abdomen and pelvis;
3. Diagnosis of antibiotic-associated diarrhea or use of antibiotics within four weeks before enrollment;
4. Presence of intestinal comorbidities, including inflammatory bowel disease or pseudomembranous colitis;
5. Presence of severe conditions rendering the patient unsuitable for inclusion;
6. Experience of bowel surgery for RE-associated fistula.