title: Prognostic value of poorly differentiated clusters in invasive breast cancer.
abstract: BACKGROUND
  Our study aimed to assess the prognostic value of poorly differentiated clusters (PDCs) in invasive breast cancer.
  
  
  METHODS
  A total of 146 cases of operable invasive ductal carcinoma that was not otherwise specified (IDC-NOS), from 2002 to 2009, were pathologically reviewed. Cancer clusters with five or more cancer cells and lacking gland-like structures were counted from a field containing maximum clusters in H & E slides under a×20 objective lens (0.950 mm2 field of vision).
  
  
  RESULTS
  Tumors with <5, 5 to 9, and ≥10 clusters were graded as G1, G2, and G3, respectively (n=41, 60, and 45 tumors, respectively). An interobserver test showed good reproducibility, with a Cohen's kappa coefficient of 0.739. The PDC grade was significantly associated with N stage (P<0.001), lymphovascular invasion (P=0.007), tumor budding grade (P<0.001), relapse rate (P<0.001), and death rate (P<0.001). Survival analyses revealed that the PDC grade was a significant prognostic factor for disease-free survival (hazard ratio 3.811; P<0.001) and overall survival (hazard ratio 3.730; P=0.001), independent of T stage, N stage, or tumor budding grade.
  
  
  CONCLUSIONS
  The PDC grade is an independent prognostic factor of IDC-NOS. Considering the simplicity and availability of this method relative to conventional clinical pathology, PDCs may serve as a novel prognostic histological characteristic in IDC-NOS.
authors.forename: Ying
authors.initials: Y
authors.lastname: Sun
authors.forename: Fenli
authors.initials: F
authors.lastname: Liang
authors.forename: Wei
authors.initials: W
authors.lastname: Cao
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.forename: Jianjun
authors.initials: J
authors.lastname: He
authors.forename: Hongyan
authors.initials: H
authors.lastname: Wang
authors.affiliation: Center for Cancer Research, Department of Pathology, the First Affiliated Hospital of Xi'an Jiaotong University, 710061 Xi'an, China. wangyili@mail.xjtu.edu.cn.
authors.forename: Yili
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000401:mortality / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D060787:Neoplasm Grading; D015588:Observer Variation; D011379:Prognosis; D015203:Reproducibility of Results; D016019:Survival Analysis