By 2030, pancreatic cancer is projected to become the second leading cause of cancer-related deaths, with a 5-year survival rate below 10%. Approximately 20% of patients are diagnosed at a borderline resectable or resectable stage, and surgical resection remains the only curative option. However, total pancreatectomy (TP) often leads to severe diarrhea (incidence rate: 43.5%) due to exocrine insufficiency, and current pancreatic enzyme replacement therapy shows limited efficacy in some patients.

Recent studies highlight the critical role of gut microbiota in pancreatic cancer progression and postoperative recovery. Patients with pancreatic ductal adenocarcinoma (PDAC) exhibit a 1000-fold increase in intrapancreatic bacterial load compared to normal tissues, with significantly elevated Bacteroides abundance and reduced Firmicutes and Proteobacteria in fecal samples. Postoperative dysbiosis is linked to complications; for example, diarrhea after cholecystectomy is dominated by Proteobacteria, suggesting that microbial imbalance may underlie diarrhea following TP.

To address this, the study proposes fecal microbiota transplantation (FMT) via oral capsules. FMT has proven effective in treating recurrent Clostridium difficile infection by restoring healthy microbiota. This research will systematically evaluate the efficacy and safety of FMT in alleviating post-TP diarrhea through clinical indicators and 16S rDNA sequencing, offering novel insights into postoperative management of pancreatic cancer.

Inclusion Criteria:

1. Age ≥18 years, regardless of gender.
2. Anticipated survival ≥3 months.
3. Severe post-total pancreatectomy diarrhea (as per HART score).
4. Willing and able to provide written informed consent and complete follow-up assessments.
5. Eastern Cooperative Oncology Group (ECOG) performance status score of 1-3.
6. No use of oral/intravenous broad-spectrum antibiotics within 3 days prior to enrollment.
7. Ability to swallow capsules intact without chewing.
8. Adequate organ function confirmed by screening-phase laboratory tests.

Exclusion Criteria:

1. Major organ insufficiency/failure, including but not limited to:

   Cardiac insufficiency or heart failure Renal insufficiency or renal failure Hepatic insufficiency or liver failure

2. Uncontrolled or severe infections.

3. Documented history of:

   Psychoactive drug abuse Alcoholism Illicit drug use

4. Severe infections complicated by sepsis or septicemia.

5. History of severe allergic reactions or known hypersensitivity to components of liquid live-bacterial enteric-coated capsules.

6. Pregnancy or lactation, or women of childbearing potential refusing contraceptive measures during the 15-week observation period.

7. Gastrointestinal perforation and/or fistulas.

8. Other conditions deemed ineligible by the investigator.