Oxidative Stress and Inflammation in Colorectal Cancer–Redox–Immune Crosstalk, Biomarkers, and Translational Implications: A Qualitative Systematic Review

Oxidative stress and chronic inflammation are tightly interconnected biological processes that play central roles in colorectal cancer (CRC) initiation, progression, and resistance to therapy. Understanding their reciprocal interactions may identify novel biomarkers and therapeutic targets with translational relevance. METHODS: This systematic review with qualitative synthesis was conducted in accordance with the PRISMA 2020 guidelines. A comprehensive literature search of PubMed/MEDLINE, Scopus, Web of Science, and Google Scholar was performed from January 2005 to June 2025. Eligible studies investigated mechanistic links between oxidative stress and inflammation in colorectal cancer, assessed oxidative or inflammatory biomarkers, or explored redox- and inflammation-targeted therapeutic strategies. Study selection and data extraction were performed systematically. Due to heterogeneity in study designs and outcomes, a qualitative synthesis was undertaken without meta-analysis. RESULTS: -isoprostanes, C-reactive protein, interleukin-6, and tumor necrosis factor-α were frequently associated with tumor stage, prognosis, and treatment response. Therapeutic strategies targeting oxidative stress and inflammation showed promising preclinical and early translational results, particularly in combination with chemotherapy or immunotherapy. CONCLUSION: Oxidative stress and inflammation constitute a synergistic axis that critically influences colorectal cancer biology. Although several biomarkers and redox-targeted interventions demonstrate translational potential, robust clinical validation is still required before routine implementation. Integrative strategies guided by biomarker profiling may represent a future direction for personalized CRC management. Most therapeutic approaches discussed are supported by preclinical and early translational evidence, and their clinical applicability remains to be validated.