title: Metaplastic breast cancer: clinicopathological features and its prognosis.
abstract: OBJECTIVE
  The prognosis of metaplastic breast cancer (MBC) is reportedly worse than that of triple-negative invasive ductal carcinoma (TN-IDC), but the determinants of poor prognosis are not yet known.
  
  
  METHODS
  Patients from two Korean cancer centres were included in this study (67 MBC and 520 TN-IDC). Characteristics of the two disease groups, including clinical parameters, histological features, chemoresponsiveness, disease recurrence and survival estimates, were evaluated.
  
  
  RESULTS
  MBC presented with larger tumours, more frequent distant metastasis and higher histological grade compared with TN-IDC (p<0.001). All but nine patients with MBC had triple-negative disease. Disease-free survival and overall survival (OS) of MBC were worse than TN-IDC (p<0.001). Multivariable analysis of disease-free survival revealed MBC type as an independent prognostic factor (HR 2.53; 95% CI 1.32 to 4.84) along with lymph node metastasis and implementation of breast conserving surgery. For OS, MBC type remained a significant prognostic factor (HR 2.56; 95% CI 1.18 to 5.54). Chemoresponsiveness of MBC and TN-IDC were similar in both neoadjuvant (p=1.000) and advanced disease settings (p=0.508). For a given MBC type, risk factors for disease recurrence included the presence of a squamous component (HR 4.0; 95% CI 1.46 to 10.99) and lymph node metastasis (HR 4.76; 95% CI 1.67 to 13.60); the risk factor for OS was initial distant metastasis (HR 10.77; 95% CI 2.59 to 44.76).
  
  
  CONCLUSIONS
  MBC had worse survival outcomes compared with TN-IDC. Poor prognosis for MBC was likely caused by frequent recurrence with high initial stage and the unique biology of MBC itself.
authors.affiliation: Center for Clinical Trials, National Cancer Center, Goyang, Korea.
authors.forename: Hyewon
authors.initials: H
authors.lastname: Lee
authors.forename: So-Youn
authors.initials: SY
authors.lastname: Jung
authors.forename: Jae Yun
authors.initials: JY
authors.lastname: Ro
authors.forename: Youngmee
authors.initials: Y
authors.lastname: Kwon
authors.forename: Joo Hyuk
authors.initials: JH
authors.lastname: Sohn
authors.forename: In Hae
authors.initials: IH
authors.lastname: Park
authors.forename: Keun Seok
authors.initials: KS
authors.lastname: Lee
authors.forename: Seeyoun
authors.initials: S
authors.lastname: Lee
authors.forename: Seok Won
authors.initials: SW
authors.lastname: Kim
authors.forename: Han Sung
authors.initials: HS
authors.lastname: Kang
authors.forename: Kyoung Lan
authors.initials: KL
authors.lastname: Ko
authors.forename: Jungsil
authors.initials: J
authors.lastname: Ro
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000737:chemistry / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry / Q000188:drug therapy / Q000401:mortality / Q000556:secondary*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D015412:Mastectomy, Segmental / Q000379:methods; D008679:Metaplasia; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D056910:Republic of Korea / Q000453:epidemiology; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human