title: C-stage in colon cancer: implications of carcinoembryonic antigen biomarker in staging, prognosis, and management.
abstract: BACKGROUND
  The American Joint Committee on Cancer (AJCC) has proposed the inclusion of pretreatment serum carcinoembryonic antigen (CEA) level (C-stage) into the conventional TNM staging system of colon cancer. We assessed the prognosis of various stages of colon cancer after such an inclusion.
  
  
  METHODS
  Data for all patients (N = 17 910) diagnosed with colonic adenocarcinoma (AJCC stages I, IIA, IIB, IIC, IIIA, IIIB, IIIC, and IV, based on TNM staging system) between January 1, 2004, and December 31, 2004, with a median follow-up of 27 months (range 0-35 months), were collected from the Surveillance, Epidemiology, and End Results database. C-stage (C0-stage = normal CEA level; C1-stage = elevated CEA level) was assigned to all patients with available CEA information (n = 9083). Multivariable analyses using Cox proportional hazards models were used to identify independent factors associated with prognosis. Prognosis of overall stages (AJCC stages I-IV and C0 or C1) was analyzed using Kaplan-Meier survival curves. All statistical tests were two-sided.
  
  
  RESULTS
  C1-stage was independently associated with a 60% increased risk of overall mortality (hazard ratio of death = 1.60, 95% confidence interval = 1.46 to 1.76, P < .001). Overall survival was decreased in patients with C1-stage cancer compared with C0-stage cancer of the respective overall stages (P < .05). Similarly, decreased overall survival was noted in patients with stage I C1 cancer compared with stage IIA C0 or stage IIIA C0 cancer (P < .001), in patients with stage IIA C1 cancer compared with stage IIIA C0 (P < .001), and in patients with stage IIB C1 or stage IIC C1 cancer compared with stage IIIB C0 cancer (P < .001).
  
  
  CONCLUSIONS
  C-stage was an independent prognostic factor for colon cancer. The results support routine preoperative CEA testing and C-staging upon diagnosis of colon cancer and the inclusion of C-stage in the conventional TNM staging of colon cancer.
authors.affiliation: Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15232, USA.
authors.forename: Pragatheeshwar
authors.initials: P
authors.lastname: Thirunavukarasu
authors.forename: Shyamsunder
authors.initials: S
authors.lastname: Sukumar
authors.forename: Magesh
authors.initials: M
authors.lastname: Sathaiah
authors.forename: Meredith
authors.initials: M
authors.lastname: Mahan
authors.forename: Kothai Divya
authors.initials: KD
authors.lastname: Pragatheeshwar
authors.forename: James F
authors.initials: JF
authors.lastname: Pingpank
authors.forename: Herbert
authors.initials: H
authors.lastname: Zeh
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Bartels
authors.forename: Kenneth K W
authors.initials: KK
authors.lastname: Lee
authors.forename: David L
authors.initials: DL
authors.lastname: Bartlett
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000453:epidemiology / Q000276:immunology* / Q000473:pathology*; D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000097:blood*; D002272:Carcinoembryonic Antigen / Q000097:blood*; D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000188:drug therapy / Q000453:epidemiology / Q000276:immunology* / Q000473:pathology*; D015986:Confounding Factors, Epidemiologic; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging / Q000379:methods; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012307:Risk Factors; D018426:SEER Program; D014481:United States / Q000453:epidemiology
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen