title: Prognostic impact of Ki-67 overexpression in subgroups categorized according to St. Gallen with early stage breast cancer.
abstract: BACKGROUND
  Ki-67 overexpression has been reported to be related to a poor prognosis for early stage breast cancer. We analyzed whether Ki-67 has a prognostic impact on risk subgroups based on the recommendations at St. Gallen in 2007.
  
  
  METHODS
  To determine the impact of Ki-67 on each risk group, a retrospective analysis was performed in patients with breast cancer who underwent curative surgery. Ki-67 was examined by immunohistochemistry with a predefined cutoff level of 10%.
  
  
  RESULTS
  A total of 1,166 patients were eligible for this analysis. During the follow-up period, distant metastasis was observed in 164 patients (14.1%), and 80 patients (6.9%) died. Ki-67 overexpression (Ki-67 ≥ 10%) was identified as an independent prognostic factor for distant-metastatic-free survival (DFS) and overall survival (OS) by univariate and multivariate analysis. In the intermediate-risk group, the difference between Ki-67 overexpression and no overexpression was statistically significant in 5-year DFS (90.9 vs. 83.4%, p = 0.002) and OS (98.1 vs. 95.8%, p = 0.002). However, in both the low- and high-risk groups, Ki-67 overexpression was not an independent prognostic factor for either 5-year DFS or OS.
  
  
  CONCLUSIONS
  Ki-67 overexpression indicates an unfavorable prognostic impact for DFS and OS. However, this impact is restricted only to those patients classified at intermediate risk.
authors.affiliation: Department of Oncology and Hematology, National Cancer Center Hospital East, Chiba, Japan. nmatsuba@east.ncc.go.jp
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Matsubara
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Mukai
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Itoh
authors.forename: Shunji
authors.initials: S
authors.lastname: Nagai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D019394:Ki-67 Antigen / Q000096:biosynthesis* / Q000235:genetics; D008875:Middle Aged; D015999:Multivariate Analysis; D009362:Neoplasm Metastasis; D011379:Prognosis; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen