title: Outcomes of Estrogen Receptor Negative and Progesterone Receptor Positive Breast Cancer.
abstract: OBJECTIVE
  To describe the clinical features and outcomes of estrogen receptor negative (ER-) and progesterone receptor positive (PgR+) breast cancer.
  
  
  METHODS
  We retrospectively reviewed a well-characterized database of sequential patients diagnosed with early stage invasive breast carcinoma. Outcomes of interest were time to relapse (TTR) and overall survival (OS). Multivariable Cox proportional hazards analysis was conducted to assess the association of ER-/PgR+ with TTR and OS in comparison to ER+ and to ER- and PgR negative (ER-/PgR-) tumors irrespective of HER2 status. ER and PgR expression was conservatively defined as 10% or greater staining of cancer cells.
  
  
  RESULTS
  815 patients were followed for a median of 40.5 months; 56 patients (7%) had ER-/PgR+, 624 (77%) had ER+ and 136 (17%) had ER-/PgR- phenotypes. Compared with ER+ tumors, ER-/PgR+ tumors were associated with younger age (50 versus 59 years, p=0.03), high grade (50% versus 24%, p<0.001) and more frequent HER2 overexpression/amplification (43% versus 14%, p<0.001). TTR for ER-/PgR+ was intermediate between ER+ and ER-/PgR- tumors, but was not significantly different from ER+ tumors. Recurrences in the ER-/PgR+ and ER-/PgR- groups occurred early in follow-up while in ER+ tumors recurrences continued to occur over the duration of follow-up. OS of ER-/PgR+ was similar to ER+ tumors and better than that of ER-/PgR- tumors.
  
  
  CONCLUSIONS
  The ER-/PgR+ phenotype is associated with higher grade with HER2 overexpression/amplification and occurs more commonly in younger women. Risk of relapse and death more closely resembles ER+ than ER-/PgR- tumors suggesting this phenotype represents a group of more aggressive hormone receptor positive tumors.
authors.affiliation: Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, Toronto, ON, Canada; Department of Medicine, University of Toronto, Toronto, ON, Canada.
authors.forename: Melissa
authors.initials: M
authors.lastname: Chan
authors.affiliation: Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
authors.forename: Martin C
authors.initials: MC
authors.lastname: Chang
authors.affiliation: Escuela de Enfermeria, Universidad de Salamanca, Salamanca, Spain.
authors.forename: Rosa
authors.initials: R
authors.lastname: González
authors.affiliation: Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, ON, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
authors.forename: Belinda
authors.initials: B
authors.lastname: Lategan
authors.affiliation: Medical Oncology Department, Salamanca University Hospital, Salamanca, Spain.
authors.forename: Elvira
authors.initials: E
authors.lastname: del Barco
authors.affiliation: Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, Toronto, ON, Canada; Department of Medicine, University of Toronto, Toronto, ON, Canada.
authors.forename: Francisco
authors.initials: F
authors.lastname: Vera-Badillo
authors.affiliation: Medical Oncology Department, Salamanca University Hospital, Salamanca, Spain.
authors.forename: Paula
authors.initials: P
authors.lastname: Quesada
authors.affiliation: Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, Toronto, ON, Canada.
authors.forename: Robyn
authors.initials: R
authors.lastname: Goldstein
authors.affiliation: Servicio de Cardiología, Complejo Hospitalario de Salamanca, Salamanca, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Cruz
authors.affiliation: Medical Oncology Department and Translational Research Unit, Albacete University Hospital, Albacete, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Ocana
authors.affiliation: Medical Oncology Department, Salamanca University Hospital, Salamanca, Spain.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Cruz
authors.affiliation: Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, Toronto, ON, Canada; Department of Medicine, University of Toronto, Toronto, ON, Canada.
authors.forename: Eitan
authors.initials: E
authors.lastname: Amir
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism*; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone