Surgery and the Gastrointestinal Microbiome in Cancer: Bidirectional Impacts and Therapeutic Opportunities – a Narrative Review

Gastrointestinal cancers rank among the most common malignancies globally, and although surgical resection remains the cornerstone of curative therapy, it is associated with considerable postoperative morbidity and mortality. Emerging evidence suggests that the gut microbiome is a critical determinant in the pathogenesis of postoperative complications, including surgical site infections, anastomotic leakage, and postoperative ileus. Microbiome-targeted interventions - including probiotics, prebiotics, and synbiotics - have shown promise in modulating microbial communities and supporting postoperative recovery; however, clinical efficacy remains inconsistent, and standardized perioperative protocols are yet to be established. This review summarizes current evidence on the interactions between gastrointestinal cancer surgery and the perioperative gut microbiome, emphasizing opportunities to harness microbiome-targeted interventions to reduce complications and enhance recovery.