title: Prognostic factors in metaplastic carcinoma of the breast: a multi-institutional study.
abstract: BACKGROUND
  Metaplastic breast carcinoma (MBC) is a rare type of breast cancer that has basal-like characteristics and is perceived to have poorer prognosis when compared with conventional no specific type/ductal carcinomas (ductal/NST). However, current data on MBC are largely derived from small case series or population-based reports. This study aimed to assess the clinicopathological features and outcome of MBC identified through an international multicentre collaboration.
  
  
  METHODS
  A large international multicentre series of MBC (no=405) with histological confirmation and follow-up information has been included in this study. The prognostic value of different variables and outcome has been assessed and compared with grade, nodal status and ER/HER2 receptor-matched ductal/NST breast carcinoma.
  
  
  RESULTS
  The outcome of MBC diagnosed in Asian countries was more favourable than those in Western countries. The outcome of MBC is not different from matched ductal/NST carcinoma but the performance of the established prognostic variables in MBC is different. Lymph node stage, lymphovascular invasion and histologic subtype are associated with outcome but tumour size and grade are not. Chemotherapy was associated with longer survival, although this effect was limited to early-stage disease. In this study no association between radiotherapy and outcome was identified. Multivariate analysis of MBC shows that histologic subtype is an independent prognostic feature.
  
  
  CONCLUSIONS
  This study suggests that MBC is a heterogeneous disease. Although the outcome of MBC is not different to matched conventional ductal/NST breast carcinoma, its behaviour is dependent on the particular subtype with spindle cell carcinoma in particular has an aggressive biological behaviour. Management of patients with MBC should be based on validated prognostic variables.
authors.affiliation: Department of Histopathology, Nottingham University Hospitals NHS Trust, and the University of Nottingham, Nottingham City Hospital, Nottingham, UK.
authors.forename: E A
authors.initials: EA
authors.lastname: Rakha
authors.affiliation: Department of Pathology, Singapore General Hospital, College Road, Singapore, Singapore.
authors.forename: P H
authors.initials: PH
authors.lastname: Tan
authors.affiliation: Institute of Surgical Pathology, University Hospital Zurich, Schmelzbergstrasse 12, CH-8091 Zurich, Switzerland.
authors.forename: Z
authors.initials: Z
authors.lastname: Varga
authors.affiliation: Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, Hong Kong.
authors.forename: G M
authors.initials: GM
authors.lastname: Tse
authors.affiliation: Department of Cellular Pathology, Queen Elizabeth Hospital Birmingham, Birmingham, UK.
authors.forename: A M
authors.initials: AM
authors.lastname: Shaaban
authors.affiliation: Department of Pathology-IDIBELL, Bellvitge University Hospital-ICS, L'Hospitalet de Llobregat, Barcelona, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Climent
authors.affiliation: Department of Pathology, Erasmus Medical Center Rotterdam, Rotterdam, The Netherlands.
authors.forename: C H M
authors.initials: CH
authors.lastname: van Deurzen
authors.affiliation: Department of Cellular Pathology, UHL Glenfield Hospital, Leicester, UK.
authors.forename: D
authors.initials: D
authors.lastname: Purnell
authors.affiliation: St James's Institute Of Oncology, St James's University Hospital, Leeds, UK.
authors.forename: D
authors.initials: D
authors.lastname: Dodwell
authors.affiliation: Department of Pathology, Kwong Wah Hospital, Kowloon, Hong Kong.
authors.forename: T
authors.initials: T
authors.lastname: Chan
authors.affiliation: Department of Histopathology, Nottingham University Hospitals NHS Trust, and the University of Nottingham, Nottingham City Hospital, Nottingham, UK.
authors.forename: I O
authors.initials: IO
authors.lastname: Ellis
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D018270:Carcinoma, Ductal, Breast / Q000401:mortality / Q000556:secondary* / Q000628:therapy; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D016896:Treatment Outcome