title: Intermittent letrozole therapy for metastatic breast cancer: case reports and literature review.
authors.affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA.
authors.forename: Lei
authors.initials: L
authors.lastname: Fan
authors.affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA.
authors.forename: Pedro E R
authors.initials: PE
authors.lastname: Liedke
authors.affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Isakoff
authors.affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA.
authors.forename: Jessica
authors.initials: J
authors.lastname: St Louis
authors.affiliation: Fox Chase Cancer Center, Philadelphia, PA.
authors.forename: Paula D
authors.initials: PD
authors.lastname: Ryan
authors.affiliation: Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA. Electronic address: pgoss@partners.org.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Goss
mesh_terms: D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D047072:Aromatase Inhibitors / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D017322:Clinical Trials, Phase II as Topic; D005260:Female; D006801:Humans; D000077289:Letrozole; D015337:Multicenter Studies as Topic; D009367:Neoplasm Staging; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy* / Q000378:metabolism / Q000556:secondary; D009570:Nitriles / Q000627:therapeutic use*; D011379:Prognosis; D011960:Receptors, Estrogen / Q000378:metabolism; D012196:Review Literature as Topic; D014230:Triazoles / Q000627:therapeutic use*
chemical_list: D047072:Aromatase Inhibitors; D009570:Nitriles; D011960:Receptors, Estrogen; D014230:Triazoles; D000077289:Letrozole
keywords: Aromatase inhibitor; Discontinuous therapy; Disease resistance