title: Concordance of Carcinoembryonic Antigen Ratio and Response Evaluation Criteria in Solid Tumors as Prognostic Surrogate Indicators of Metastatic Colorectal Cancer Patients Treated with Chemotherapy.
abstract: BACKGROUND
  Carcinoembryonic antigen (CEA) is widely used as a tumor marker in colorectal cancer (CRC). This study aimed to evaluate the role of the degree of change in CEA levels during the treatment period and found that the degree of change highly correlated with disease survival and Response Evaluation Criteria in Solid Tumors (RECIST) criteria in evaluating therapy response.
  
  
  METHODS
  A total of 447 metastatic CRC patients treated with surgery of the primary tumor followed by systemic therapy at a single center from the year 2000 through 2011 were reviewed. The degree of change in CEA levels was expressed as the CEA ratio (post-CEA/pre-CEA) and classified into four groups during the treatment period for further evaluation. The imaging change of the same population was also compared with the CEA ratio during the treatment period.
  
  
  RESULTS
  The CEA ratio was significantly correlated with different chemotherapy regimens (p < 0.001), pre-treatment CEA level (p < 0.001), lymphovascular invasion (p = 0.006), and tumor differentiation (p = 0.018). CEA ratio and imaging change according to RECIST criteria were both correlated with overall survival (p < 0.001). These two methods for evaluating treatment response were highly correlated (p < 0.001).
  
  
  CONCLUSIONS
  CEA ratio was found to be a reliable prognostic factor in stage IV CRC, and was highly correlated with the imaging survey according to RECIST criteria. Further prospective studies are essential to validate these findings.
authors.affiliation: Division of Colon and Rectal Surgery, Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Sheng-Chieh
authors.initials: SC
authors.lastname: Huang
authors.forename: Jen-Kou
authors.initials: JK
authors.lastname: Lin
authors.forename: Tzu-Chen
authors.initials: TC
authors.lastname: Lin
authors.forename: Wei-Shone
authors.initials: WS
authors.lastname: Chen
authors.forename: Shung-Haur
authors.initials: SH
authors.lastname: Yang
authors.forename: Huann-Sheng
authors.initials: HS
authors.lastname: Wang
authors.forename: Yuan-Tzu
authors.initials: YT
authors.lastname: Lan
authors.forename: Chun-Chi
authors.initials: CC
authors.lastname: Lin
authors.forename: Jeng-Kai
authors.initials: JK
authors.lastname: Jiang
authors.forename: Shih-Ching
authors.initials: SC
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000097:blood; D002272:Carcinoembryonic Antigen / Q000097:blood*; D015179:Colorectal Neoplasms / Q000097:blood* / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008113:Liver Neoplasms / Q000097:blood* / Q000188:drug therapy* / Q000401:mortality / Q000556:secondary; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D066066:Response Evaluation Criteria in Solid Tumors; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen