title: Oestrogen receptor downregulation: an opportunity for extending the window of endocrine therapy in advanced breast cancer.
abstract: BACKGROUND
  Advanced breast cancer is largely incurable and current treatment modalities are aimed towards restricting tumour growth, prolonging survival, palliating symptoms and maintaining quality of life (QoL). The development of breast cancer is strongly influenced by endogenous oestrogens (and other growth factors), leading to a strong focus on the development of antioestrogenic compounds for the treatment of hormone-sensitive advanced disease.
  
  
  METHODS
  This is a review of current endocrine therapies available for postmenopausal women with advanced breast cancer, examining the likely impact of newer agents on treatment strategies.
  
  
  RESULTS
  In postmenopausal women, current treatment options include tamoxifen, aromatase inhibitors (AIs) and megestrol acetate. Fulvestrant ('Faslodex') is a new, well-tolerated, oestrogen receptor antagonist that has no known agonist effect and is at least as effective as the AI anastrozole for the treatment of postmenopausal patients with metastatic or advanced breast cancer who have progressed on prior endocrine therapy. Fulvestrant maintains QoL throughout successful treatment.
  
  
  CONCLUSIONS
  Fulvestrant represents a new treatment option for postmenopausal women with advanced disease. New agents that appear to lack cross-resistance with existing treatments may be used to extend the time period during which endocrine therapy may be employed before the need for cytotoxic chemotherapy.
authors.affiliation: Chemotherapy Unit, Internal Medicine and Oncology, Jules Bordet Institute, Brussels, Belgium. martine.piccart@bordet.be
authors.forename: M
authors.initials: M
authors.lastname: Piccart
authors.forename: L M
authors.initials: LM
authors.lastname: Parker
authors.forename: K I
authors.initials: KI
authors.lastname: Pritchard
mesh_terms: D000368:Aged; D047072:Aromatase Inhibitors; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000503:physiopathology*; D015536:Down-Regulation; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004965:Estrogen Antagonists / Q000494:pharmacology*; D005260:Female; D000077267:Fulvestrant; D006801:Humans; D019290:Megestrol Acetate; D008875:Middle Aged; D017698:Postmenopause; D011379:Prognosis; D011788:Quality of Life; D011960:Receptors, Estrogen / Q000187:drug effects* / Q000502:physiology*; D013629:Tamoxifen / Q000494:pharmacology*
chemical_list: D047072:Aromatase Inhibitors; D004791:Enzyme Inhibitors; D004965:Estrogen Antagonists; D011960:Receptors, Estrogen; D013629:Tamoxifen; D000077267:Fulvestrant; D004958:Estradiol; D019290:Megestrol Acetate