title: A randomised comparison of oestrogen suppression with anastrozole and formestane in postmenopausal patients with advanced breast cancer.
abstract: The relative efficacy and tolerability of the aromatase inhibitors anastrozole (Arimidex) and formestane are assessed in a direct comparative trial in postmenopausal women with advanced breast cancer. Final results are available and reported here only for oestradiol suppression. Patients were randomised to receive either oral anastrozole, 1 mg once daily, or formestane, 250 mg every 2 weeks intramuscularly. In the anastrozole group, mean serum oestradiol levels fell from 32.1 pmol/l at baseline to 6.5 pmol/l at week 1, and similar levels of suppression were maintained over the next 3 weeks. In the formestane group, mean serum oestradiol levels fell from 31.0 pmol/l at baseline to 9.5 pmol/l at the week 1 assessment. In this group, serum oestradiol levels tended to rise by the 2- and 4-week measurements, i.e. immediately before the next injection was due. Based on the 2- and 4-week measurements, the mean falls in oestradiol levels were 79 and 58% in the anastrozole and formestane groups, respectively (p = 0.0001). More effective and consistent suppression of oestradiol was achieved with anastrozole at the therapeutic dose of 1 mg once daily, orally, than with formestane at the standard dose of 250 mg every 2 weeks, intramuscularly.
authors.forename: U R
authors.initials: UR
authors.lastname: Kleeberg
authors.forename: M
authors.initials: M
authors.lastname: Dowsett
authors.forename: R P
authors.initials: RP
authors.lastname: Carrion
authors.forename: D J
authors.initials: DJ
authors.lastname: Dodwell
authors.forename: D A
authors.initials: DA
authors.lastname: Vorobiof
authors.forename: L A
authors.initials: LA
authors.lastname: Aparicio
authors.forename: J F
authors.initials: JF
authors.lastname: Robertson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000077384:Anastrozole; D000735:Androstenedione / Q000031:analogs & derivatives* / Q000627:therapeutic use; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D047072:Aromatase Inhibitors; D001943:Breast Neoplasms / Q000097:blood* / Q000188:drug therapy* / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D004958:Estradiol / Q000097:blood*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009570:Nitriles / Q000627:therapeutic use*; D017698:Postmenopause; D016896:Treatment Outcome; D014230:Triazoles / Q000627:therapeutic use*
chemical_list: D018931:Antineoplastic Agents, Hormonal; D047072:Aromatase Inhibitors; D004791:Enzyme Inhibitors; D009570:Nitriles; D014230:Triazoles; D000077384:Anastrozole; D000735:Androstenedione; D004958:Estradiol; C014594:formestane