title: Progesterone receptor expression is an independent prognostic variable in early breast cancer: a population-based study.
abstract: BACKGROUND
  Progesterone receptor (PR) expression assessment in early invasive breast cancer remains controversial. This study sought to re-evaluate PR expression as a potential therapeutic guide in early breast cancer; particularly in oestrogen receptor (ER)-positive, lymph node (LN)-negative disease.
  
  
  METHODS
  A population cohort of 1074 patients presenting to a single Cancer Centre over 4 years (2000-2004) underwent surgery for primary invasive breast cancer with curative intent. Prospective data collection included patient demographics, pathology, ER and PR expression, HER2 status, adjuvant chemotherapy and endocrine therapy. Progesterone receptor expression was compared with (all causes) overall survival (OS), breast cancer-specific survival (BCSS) and disease-free survival (DFS).
  
  
  RESULTS
  Overall survival was 71.0% and BCSS was 83.0% at median follow-up of 8.34 years. Absent PR expression was significantly associated with poorer prognosis for OS, BCSS and DFS (P<0.0001, log-rank), even within the ER-positive, LN-negative group (hazard ratio for BCSS 3.17, 95% CI 1.43-7.01) and was not influenced by endocrine therapy. Cox's regression analysis demonstrated that PR expression was an independent prognostic variable.
  
  
  CONCLUSIONS
  Absence of PR expression is a powerful, independent prognostic variable in operable, primary breast cancer even in ER-positive, LN-negative patients receiving endocrine therapy. Absence of PR expression should be re-evaluated as a biomarker for poor prognosis in ER-positive breast cancer and such patients considered for additional systemic therapy.
authors.affiliation: Pathology Department, Ninewells Hospital & Medical School, Dundee DD1 9SY, UK.
authors.forename: C A
authors.initials: CA
authors.lastname: Purdie
authors.affiliation: Dundee Cancer Centre, University of Dundee, Ninewells Hospital & Medical School, Dundee DD1 9SY, UK.
authors.forename: P
authors.initials: P
authors.lastname: Quinlan
authors.affiliation: Pathology Department, Ninewells Hospital & Medical School, Dundee DD1 9SY, UK.
authors.forename: L B
authors.initials: LB
authors.lastname: Jordan
authors.affiliation: Dundee Cancer Centre, University of Dundee, Ninewells Hospital & Medical School, Dundee DD1 9SY, UK.
authors.forename: A
authors.initials: A
authors.lastname: Ashfield
authors.affiliation: Public Health Section, Community Health Sciences University of Dundee, Dundee DD2 4BF, UK.
authors.forename: S
authors.initials: S
authors.lastname: Ogston
authors.affiliation: Dundee Cancer Centre, University of Dundee, Ninewells Hospital & Medical School, Dundee DD1 9SY, UK.
authors.forename: J A
authors.initials: JA
authors.lastname: Dewar
authors.affiliation: Dundee Cancer Centre, University of Dundee, Ninewells Hospital & Medical School, Dundee DD1 9SY, UK.
authors.forename: A M
authors.initials: AM
authors.lastname: Thompson
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000096:biosynthesis*; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D018572:Disease-Free Survival; D055088:Early Detection of Cancer; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008875:Middle Aged; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human