title: The prognostic significance of metaplastic carcinoma of the breast (MCB)--a case controlled comparison study with infiltrating ductal carcinoma.
abstract: OBJECTIVE
  Metaplastic carcinoma of the breast (MCB) is a rare histological subtype of breast cancer with an incidence of less than 0.1%-0.5%. Due to its rarity, the clinical characteristics and prognostic significance of MCB compared with other common breast cancers (like infiltrating ductal carcinoma [IDC], and infiltrating lobular carcinoma [ILC]) are not clear, and controversial among different reports.
  
  
  METHODS
  We performed a collective comparison study of multi-institutional cases to evaluate the clinical characteristics and prognostic status of MCB to compare with IDC and ILC. A case control analysis was performed to minimize the bias from clinicopathologic factors between IDC and MCB. Disease free survival (DFS) and overall survival (OS) between groups were compared.
  
  
  RESULTS
  Forty-five MCB patients were enrolled from the 4 medical centers and compared with 1777 IDC and 53 ILC patients from the CCH cancer registry database comprise the current study. Compared with IDC, MCB was associated with older age, larger tumor size, a lesser lymph node positive rate, a higher likelihood of distant metastasis, higher tumor grade, lower ER-positive tumor, and higher triple negative breast cancer subtype (TNBC). MCB was associated with worse OS (p = 0.031) than IDC, but no difference in DFS (p = 0.071); however, MCB was not statistically different from ILC in both DFS and OS (p = 0.289 and 0.132, respectively). Compared with the case-controlled IDC group, MCB patients had poorer OS (p = 0.040), but no difference in DFS (p = 0.439).
  
  
  CONCLUSIONS
  MCB is associated with poorer OS than IDC, and this was related to tumor behavior rather than clinicopathologic factors.
authors.affiliation: Division of General Surgery, Changhua Christian Hospital, Changhua, Taiwan; Comprehensive Breast Cancer Center, Department of Surgery, Changhua Christian Hospital, Changhua, Taiwan; Department of Research, Changhua Christian Hospital, Changhua, Taiwan; School of Medicine, National Yang Ming University, Taipei, Taiwan. Electronic address: hwlai650420@yahoo.com.tw.
authors.forename: Hung-Wen
authors.initials: HW
authors.lastname: Lai
authors.forename: Ling-Ming
authors.initials: LM
authors.lastname: Tseng
authors.forename: Tsai-Wang
authors.initials: TW
authors.lastname: Chang
authors.forename: Yao-Lung
authors.initials: YL
authors.lastname: Kuo
authors.forename: Chia-Ming
authors.initials: CM
authors.lastname: Hsieh
authors.forename: Shou-Tung
authors.initials: ST
authors.lastname: Chen
authors.forename: Sou-Jen
authors.initials: SJ
authors.lastname: Kuo
authors.forename: Chin-Cheng
authors.initials: CC
authors.lastname: Su
authors.forename: Dar-Ren
authors.initials: DR
authors.lastname: Chen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001943:Breast Neoplasms / Q000737:chemistry / Q000473:pathology*; D002277:Carcinoma / Q000737:chemistry / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry / Q000473:pathology; D018275:Carcinoma, Lobular / Q000737:chemistry / Q000473:pathology; D016022:Case-Control Studies; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008875:Middle Aged; D060787:Neoplasm Grading; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D012189:Retrospective Studies; D015996:Survival Rate; D064726:Triple Negative Breast Neoplasms / Q000473:pathology; D047368:Tumor Burden
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human
keywords: Histologic tumor grade; Infiltrating ductal carcinoma (IDC); Infiltrating lobular carcinoma (ILC); Metaplastic carcinoma of the breast (MCB); Triple negative breast cancer (TNBC)