Impact of Gut Microbiota on the Clinical Course and Treatment Outcomes of Colorectal Cancer-A Systematic Review

As This systematic review aims to present the available data on the role of gut microbiota in colorectal cancer diagnosis, prognosis, and treatment response. Thirty-six studies met the inclusion criteria, encompassing case-control cohorts, prospective survival analyses, and early-phase translational trials. Across populations and sequencing methodologies, gut microbiome alterations were consistently identified, with enrichment of oral-derived anaerobes, particularly Fusobacterium nucleatum, and depletion of beneficial commensal taxa in CRC patients compared with controls. Several stool-based multi-species classifiers demonstrated good to excellent diagnostic performance, particularly when combined with established screening modalities. Tumor-associated microbial signatures were further associated with adverse survival outcomes and, in exploratory cohorts, with differential treatment response. Emerging evidence suggests that the microbiome may represent a modifiable environmental factor, particularly relevant in early-onset CRC.The gut microbiome represents a promising adjunctive biomarker for CRC diagnosis and prognostic stratification, with potential implications for precision oncology.