title: Neutrophil-lymphocyte ratio and CEA level as prognostic and predictive factors in colorectal cancer: A systematic review and meta-analysis.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  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.
  
  
  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.
  
  
  CONCLUSIONS
  NLR and CEA are valuable tools for the prediction of prognosis in CRC and adjusting the treatment strategy.
authors.affiliation: Department of Surgery, Division of Colorectal Surgery, Mackey Memorial Hospital, Zhongshan, Taipei, Taiwan.
authors.forename: Po-Li
authors.initials: PL
authors.lastname: Tsai
authors.affiliation: Hospice Palliative Care Center, Mackey Memorial Hospital, Tamshui District, Taipei, Taiwan.
authors.forename: Wei-Ju
authors.initials: WJ
authors.lastname: Su
authors.affiliation: Department of Surgery, Division of Colorectal Surgery, Mackey Memorial Hospital, Zhongshan, Taipei, Taiwan.
authors.forename: Wei-Hung
authors.initials: WH
authors.lastname: Leung
authors.affiliation: Department of Surgery, Division of Colorectal Surgery, Mackey Memorial Hospital, Zhongshan, Taipei, Taiwan.
authors.forename: Cheng-Ta
authors.initials: CT
authors.lastname: Lai
authors.affiliation: Department of Surgery, Division of Colorectal Surgery, Mackey Memorial Hospital, Zhongshan, Taipei, Taiwan.
authors.forename: Chien-Kuo
authors.initials: CK
authors.lastname: Liu
mesh_terms: D002272:Carcinoembryonic Antigen / Q000097:blood*; D015179:Colorectal Neoplasms / Q000097:blood* / Q000401:mortality; D006801:Humans; D008214:Lymphocytes; D009504:Neutrophils; D011379:Prognosis
chemical_list: D002272:Carcinoembryonic Antigen