title: Review of hormone-based treatments in postmenopausal patients with advanced breast cancer focusing on aromatase inhibitors and fulvestrant.
abstract: BACKGROUND
  Endocrine therapy constitutes a central modality in the treatment of oestrogen receptor (ER)-positive advanced breast cancer.
  
  
  OBJECTIVE
  To evaluate the evidence for endocrine treatment in postmenopausal patients with advanced breast cancer focusing on the aromatase inhibitors, letrozole, anastrozole, exemestane and fulvestrant.
  
  
  METHODS
  A review was carried out using PubMed. Randomised phase II and III trials reporting on ≥100 patients were included.
  
  
  RESULTS
  35 trials met the inclusion criteria. If not used in the adjuvant setting, a non-steroid aromatase inhibitor was the optimal first-line option. In general, the efficacy of the different aromatase inhibitors and fulvestrant was similar in tamoxifen-refractory patients. A randomised phase II trial of palbociclib plus letrozole versus letrozole alone showed significantly increased progression-free survival (PFS) when compared with endocrine therapy alone in the first-line setting (20.2 vs 10.2 months). Furthermore, the addition of everolimus to exemestane in the Breast Cancer Trials of OraL EveROlimus-2 (BOLERO-2) study resulted in an extension of median PFS by 4.5 months after recurrence/progression on a non-steroid aromatase inhibitor. However, overall survival was not significantly increased.
  
  
  CONCLUSIONS
  Conventional treatment with an aromatase inhibitor or fulvestrant may be an adequate treatment option for most patients with hormone receptor-positive advanced breast cancer. Mammalian target of rapamycin (mTOR) inhibition and cyclin-dependent kinase 4/6 (CDK4/6) inhibition might represent substantial advances for selected patients in some specific settings. However, there is an urgent need for prospective biomarker-driven trials to identify patients for whom these treatments are cost-effective.
authors.affiliation: Department of Oncology , Herlev Hospital, University of Copenhagen , Herlev , Denmark.
authors.forename: Iben
authors.initials: I
authors.lastname: Kümler
authors.affiliation: Department of Oncology , Finsen Centre, Rigshospitalet, University of Copenhagen , Copenhagen , Denmark.
authors.forename: Ann S
authors.initials: AS
authors.lastname: Knoop
authors.affiliation: Department of Oncology , Herlev Hospital, University of Copenhagen , Herlev , Denmark.
authors.forename: Christina A R
authors.initials: CA
authors.lastname: Jessing
authors.affiliation: Department of Oncology , Finsen Centre, Rigshospitalet, University of Copenhagen , Copenhagen , Denmark.
authors.forename: Bent
authors.initials: B
authors.lastname: Ejlertsen
authors.affiliation: Department of Oncology , Herlev Hospital, University of Copenhagen , Herlev , Denmark.
authors.forename: Dorte L
authors.initials: DL
authors.lastname: Nielsen
keywords: Advanced breast cancer,; Endocrine therapy