title: Incorporation of serum carcinoembryonic antigen levels into the prognostic grouping system of colon cancer.
abstract: OBJECTIVE
  This study aimed to clarify the significance of preoperative serum carcinoembryonic antigen (CEA) on disease-free survival (DFS) in colon cancer and propose a new prognostic grouping system.
  
  
  METHODS
  A multiinstitutional retrospective cohort of 7296 colon cancer patients who underwent R0 surgery between 1997 and 2006 was analyzed. We stratified preoperative serum CEA values into three categories (C-stages): C0 (normal CEA), C1A (up to double the cutoff value), and C1B (more than double the cutoff value) and stratified each TNM stage by C-stage. Multivariate analyses using Cox regression models were used to analyze the significance of C-stage on 5-year DFS.
  
  
  RESULTS
  CEA level was an independent factor affecting DFS; the 5-year DFS of patients with C0 and C1, as well as those with C1A and C1B, differed significantly (C0 84.6%, C1 69.8%, C1A 72.7%, and C1B 66.4%, P < 0.0001). Additionally, the DFS of pStages IIC and C1B was significantly lower than of pStages IIIA and C0 (65.8 vs. 87.7%, respectively; hazard ratio 3.44, 95% confidence interval 1.97-5.88, P < 0.0001). Moreover, the 5-year DFS of pStages IIIA and C0 or C1A did not differ significantly from pStages I and C1A (87.7 vs. 87.7%, P = 0.90 and 86.4 vs. 87.7%, P = 0.78, respectively).
  
  
  CONCLUSIONS
  pStage IIC and C1B disease should be considered candidates for intensive adjuvant chemotherapy. Conversely, pStages IIIA and C0 or C1A could be exempted from adjuvant chemotherapy. Incorporating C-stage into the current TNM staging system may facilitate decision making regarding the use of adjuvant chemotherapy in colon cancer patients.
authors.affiliation: Department of Surgery, Tochigi Cancer Center, 4-9-13 Yohnan, Utsunomiya, Tochigi, 320-0834, Japan. heiozawa@tochigi-cc.jp.
authors.forename: Heita
authors.initials: H
authors.lastname: Ozawa
authors.affiliation: Department of Surgery, Tochigi Cancer Center, 4-9-13 Yohnan, Utsunomiya, Tochigi, 320-0834, Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Kotake
authors.affiliation: Department of Surgery, Tochigi Cancer Center, 4-9-13 Yohnan, Utsunomiya, Tochigi, 320-0834, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Hosaka
authors.affiliation: Department of Surgery, Tochigi Cancer Center, 4-9-13 Yohnan, Utsunomiya, Tochigi, 320-0834, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Hirata
authors.affiliation: Department of Surgery, Tochigi Cancer Center, 4-9-13 Yohnan, Utsunomiya, Tochigi, 320-0834, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Nakagawa
authors.affiliation: Department of Surgery, Tochigi Cancer Center, 4-9-13 Yohnan, Utsunomiya, Tochigi, 320-0834, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Fujita
authors.affiliation: Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sugihara
mesh_terms: D000368:Aged; D002272:Carcinoembryonic Antigen / Q000097:blood*; D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000097:blood* / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009367:Neoplasm Staging; D011379:Prognosis
chemical_list: D002272:Carcinoembryonic Antigen
keywords: Adjuvant chemotherapy; Carcinoembryonic antigen (CEA); Colon cancer; Prognostic marker; TNM staging system