Patients in the control group continued their original chemotherapy/targeted therapy regimen, with each treatment cycle lasting 3 weeks, for a total of 5 cycles. Treatment efficacy was assessed after every 2 cycles.

Patients in the FMT group received treatment starting from the fourth cycle on top of their existing regimen. They underwent one FMT treatment within 3 days prior to chemotherapy/targeted therapy during the fourth, sixth, and eighth cycles (weeks 3, 9, and 15 after study initiation). Each transplant consisted of approximately 40g of donor gut microbiota encapsulated in capsules. The capsules were administered orally, typically at a dose of 2-3 capsules (1g/capsule) every 3-5 minutes, totaling 40 capsules per dose for a total of 120 capsules. Treatment cycles were conducted every 3 weeks, with therapeutic efficacy assessed after every 2 cycles.

Building upon the existing treatment regimen, starting from the fourth cycle, one FMT treatment was administered within 3 days prior to chemotherapy/targeted therapy during the fourth, sixth, and eighth cycles (weeks 3, 9, and 15 after study initiation). Each transplant consisted of approximately 40g of donor intestinal bacteria encapsulated in capsules. The capsules were administered orally, typically at a dose of 2-3 capsules (1g/capsule) every 3-5 minutes, totaling 40 capsules per dose for a total of 120 capsules. Treatment cycles were conducted every 3 weeks, with therapeutic efficacy assessed after every 2 cycles.

This outcome measure assesses the incidence (grade ≥1 per CTCAE 5.0) and improvement rate (≥1-grade reduction in symptom severity or ≥30% decrease in EORTC QLQ-C30 scores) of chemotherapy/targeted therapy-induced gastrointestinal (GI) symptoms (e.g., nausea, vomiting, diarrhea) in patients with gastrointestinal cancers receiving fecal microbiota transplantation (FMT), as determined by scale scores and adverse event grading at baseline and post-treatment follow-up.

This outcome measure assesses the incidence (grade ≥1 or exacerbation of baseline symptoms per CTCAE 5.0) and improvement rate (≥1-grade reduction in symptom severity or ≥30% decrease in GSRS scores) of chemotherapy/targeted therapy-induced gastrointestinal symptoms (e.g., nausea, vomiting) in patients with gastrointestinal cancers receiving FMT.

This secondary outcome measure compares changes in serum tumor markers (e.g., CEA, CA19-9), inflammatory factors (IL-6, IL-8, soluble Tumor Necrosis Factor Receptor 1 [sTNFR1], CRP), and Neutrophil (NE) Ratio before and after fecal microbiota transplantation (FMT) combined with chemotherapy/targeted therapy in gastrointestinal cancer patients, by detecting serum samples to evaluate the treatment's impact on tumor burden and systemic inflammatory status.