Neutrophilulymphocyte ratio and CEA level as prognostic and predictive factors in colorectal cancer: A systematic review and meta-analysis

Introduction: There is a growing body of evidence showing the functional relationship between inflammation index like netrophil.lymphocyte ratio. (NLR) and colorectal cancer. (CRC) in both experimental and clinical situations. The serum carcinoembryonic antigen. (CEA) level is the most widely used marker and associate with poor prognosis in most studies. For these factors to be clinically useful, they should be routinely available, well standardized, and validated in different patient cohorts. Aims: There is a growing body of evidence showing the functional relationship between inflammation index like netrophil-lymphocyte ratio. (NLR) and colorectal cancer. (CRC) in both experimental and clinical situations. The serum carcinoembryonic antigen. (CEA) level is the most widely used marker and associate with poor prognosis in most studies. For these factors to be clinically useful, they should be routinely available, well standardized, and validated in different patient cohorts. Materials and Methods: We systemically searched PubMed, Embase, and SciVerse Scopus databases, and performed a meta.analysis by Review Manager 5.2 software. (The Cochrane Collaboration, Software Update, Oxford). Two reviewers selected studies, assessed risk of bias, and extracted data independently. Newcastle.Ottawa Scale was applied to assess the quality of included studies. Results: Fifteen studies involving 7741 patients with CRC were analyzed. Patients with an NLR 5 before treatment were significantly more likely to have 5-year overall survival (odds ratio [OR] = 2.03; 95% confidence interval [CI] = 1.56-2.63) and 5-year disease-free survival (OR = 1.67; 95% CI = 1.19-2.35). Pretreatment CEA level 5 were significantly associated with complete tumor response and tumor downstaging after neoadjuvant treatment. The result also showed that patients with NLR 5 were expected to have a larger tumor, poorer tumor differentiation, and higher CEA level. Conclusion: NLR and CEA are valuable tools for the prediction of prognosis in CRC and adjusting the treatment strategy.