Impact of ileostomy reversal on gut microbiome and metabolome in rectal cancer: a review of mechanisms and clinical consequences

Prophylactic ileostomy is a critical measure for preventing anastomotic leakage after low rectal cancer surgery; however, the incidence of diarrhea following stoma reversal remains high, posing a major clinical challenge. Recent studies have revealed that the underlying pathophysiology involves not only anal sphincter dysfunction but also a comprehensive imbalance in the gut microbiota–metabolite–immune axis. This review systematically elucidates the dynamic evolution of the gut microbiome after stoma reversal and its interplay with host metabolism. It further delves into multidimensional pathophysiological mechanisms, including gut dysbiosis, reduced production of short-chain fatty acids, dysregulated bile acid metabolism, and impaired intestinal barrier integrity. In light of recent advances, this article analyzes the clinical characteristics and subtypes of postoperative diarrhea, summarizes precision diagnostic strategies based on multi-omics technologies, and provides an objective assessment of emerging therapies such as probiotics, fecal microbiota transplantation, metabolic interventions, and nutritional support. Finally, the necessity of establishing an integrated multidisciplinary management model is discussed, with the aim of offering new perspectives and a theoretical foundation for improving the quality of life in rectal cancer patients after surgery. Systematically elucidates the core mechanism of postoperative diarrhea after ileostomy reversal lies in the asynchrony between "anatomical continuity restoration" and "functional microbiota recovery". In-depth analysis of the cascading effects among structural gut microbiota imbalance, short-chain fatty acid and bile acid metabolic disorders, and multi-level intestinal barrier damage. Proposes a precision diagnostic classification strategy based on multi-omics (microbiome, metabolome), shifting clinical diagnosis from symptom description to mechanistic classification. Comprehensive review of the paradigm shift from traditional symptomatic treatment to emerging etiology-targeted interventions, including precision probiotics, microbiota transplantation, metabolite supplementation, and personalized nutrition. Advocates for establishing a multidisciplinary integrated management model, providing a systematic theoretical framework and practical pathway for improving postoperative quality of life in rectal cancer patients.