title: Prognostic factors for patients with stage II colon cancer:  results of a prospective study.
abstract: OBJECTIVE
  Many studies revealed that the recurrence rate of stage II colon cancer was up to 25–40 %. Regrettably, the risk factors for recurrence of stage II colon cancer remain ambiguous. So, we conducted this study to identify the clinicopathological factors associated with prognosis of stage II colon cancer.
  
  
  METHODS
  We enrolled 452 stage II colon cancer patients who underwent radical resection at Peking University Cancer Hospital between January 2007 and December 2010, and 162 patients who received adjuvant treatment were excluded.
  
  
  RESULTS
  The 5-year recurrence rate and overall survival of this cohort were 19.3 (56/290) and 75.9 % (220/290), respectively. In univariate analysis, the following variables were significantly associated with tumor recurrence:male patients (P<0.001), tumor size >5 cm (P=0.048), and preoperative carcinoembryonic antigen (CEA) level ≥ 5 ng/ml (P=0.004); the following factors were significantly associated with adverse 5-year overall survival:male patients (P<0.001), age ≥60 years old (P=0.004), less than 12 lymph nodes (P=0.006), and preoperative CEA level ≥5 ng/ml (P=0.011). In multivariate analysis,the preoperative CEA level ≥5 ng/ml (P=0.003) and male (P<0.001) were adverse variables significantly associated with tumor recurrence, and the preoperative CEA level ≥ 5 ng/ml (P=0.016), male (P<0.001), and age ≥60 years old (P=0.008) were independent prognostic factors for the 5-year overall survival rate, respectively.
  
  
  CONCLUSIONS
  The preoperative CEA level ≥5 ng/ml and male were undesirable factors significantly associated with tumor recurrence. The preoperative CEA level ≥5 ng/ml, male, and age ≥60 years old were adverse factors significantly associated with poor prognosis.
authors.forename: Chenghai
authors.initials: C
authors.lastname: Zhang
authors.forename: Jiabo
authors.initials: J
authors.lastname: Di
authors.forename: Beihai
authors.initials: B
authors.lastname: Jiang
authors.forename: Ming
authors.initials: M
authors.lastname: Cui
authors.forename: Zaozao
authors.initials: Z
authors.lastname: Wang
authors.forename: Jiadi
authors.initials: J
authors.lastname: Xing
authors.forename: Hong
authors.initials: H
authors.lastname: Yang
authors.forename: Zhendan
authors.initials: Z
authors.lastname: Yao
authors.forename: Nan
authors.initials: N
authors.lastname: Zhang
authors.forename: Xiangqian
authors.initials: X
authors.lastname: Su
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D055815:Young Adult