EC Microbiology

Colorectal cancer (CRC) is the third most common cancer worldwide; it is now being increasingly diagnosed in developing coun- tries, including India. Dysbiosis of the gut microbiota contributes importantly to the carcinogenesis via increased inflammation, production of genotoxins, and immune dysfunction. Probiotics - live organisms with a scientific definition of activity that have favor- able health effects - may serve as an adjunctive strategy for prevention and management. This transfusion-review integrates pre- clinical mechanisms, evidence from clinical trials, and translational work on probiotics in CRC. Their anticancer effects are mediated by several interconnected pathways: restoration of microbiota, butyrate production, colonization resistance, immune stimulation, strengthening of barriers, and induction of apoptosis. Robust RCTs show that it is effective in controlling chemotherapy-induced diarrhea (RR 0.51), post-operative complications (decrease from 33% to 10%), and pro-inflammatory cytokines TNF-α and IL-65. Some strains, like Lactobacillus rhamnosus GG and Bifidobacterium longum, and multispecies combinations have better effects even in small numbers. Adverse event rates are low (< 5%) in immunocompetent populations, safety profiles are excellent. Yet there are substantial gaps in knowledge: mass prophylactic trials in polyp-bearing populations are in short supply, optimal dosing regimens are unclear, and strain-specific efficacy is distinct across different genetic backgrounds. Future directions include personalized mi- crobiota profiling, integration of synbiotics, co-therapeutic synergies with immunotherapy, and multicenter trials in lower-resource settings. This synthesis highlights probiotics as multifaceted, inexpensive, evidence-based interventions across the CRC continuum- from primary prevention through to supportive care and calls for translational research integrating probiotics into clinical guide- lines, particularly in India, where CRC incidence projections indicate doubling in incidence by 2030.

 Keywords: Probiotics; Colorectal Cancer; Gut Microbiota; Dysbiosis; Clinical Trials; Lactobacillus; Bifidobacterium; Chemotherapy; Pre- vention; Therapeutic intervention

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