title: Phase III randomized adjuvant study of tamoxifen alone versus  sequential tamoxifen and anastrozole in Japanese postmenopausal  women with hormone-responsive breast cancer:   N-SAS BC03 study.
abstract: Clinical trials conducted in Western countries have shown that aromatase inhibitors are associated with better disease-free survival (DFS) than tamoxifen in postmenopausal early breast cancer. Because pharmacogenetic differences in drug-metabolizing genes may cause ethnic differences, assessment of the efficacy and tolerability of aromatase inhibitors in non-white women is warranted. This open-label, randomized clinical trial included 706 postmenopausal Japanese women with hormone-receptor-positive breast cancer, who had received tamoxifen for 1 to 4 years as adjuvant therapy. This study was closed early after entry of approximately 28% of the initially planned patients. They were randomly assigned to either switch to anastrozole or to continue tamoxifen for total treatment duration of 5 years. Primary endpoints were DFS and adverse events. At a median follow-up of 42 months, the unadjusted hazard ratio was 0.69 (95% confidence interval, 0.42-1.14; P = 0.14) for DFS and 0.54 (95% CI, 0.29-1.02; P = 0.06) for relapse-free survival (RFS), both in favor of anastrozole. The incidence of thromboembolic events in the tamoxifen group and bone fractures in the anastrozole group was not excessively high. Switching from tamoxifen to anastrozole was likely to decrease disease recurrence in postmenopausal Japanese breast cancer patients. Ethnic differences in major adverse events may be attributable to a low baseline risk of these events in Japanese.
authors.affiliation: Breast Center, Aihara Hospital, 3-4-30 Makiochi, Osaka, Minoh 562-0004, Japan. aiharat@aiharabreast.com
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Aihara
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Takatsuka
authors.forename: Shozo
authors.initials: S
authors.lastname: Ohsumi
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Aogi
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Hozumi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Imoto
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Mukai
authors.forename: Hiroji
authors.initials: H
authors.lastname: Iwata
authors.forename: Toru
authors.initials: T
authors.lastname: Watanabe
authors.forename: Chikako
authors.initials: C
authors.lastname: Shimizu
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakagami
authors.forename: Motoshi
authors.initials: M
authors.lastname: Tamura
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Ito
authors.forename: Norikazu
authors.initials: N
authors.lastname: Masuda
authors.forename: Nobuo
authors.initials: N
authors.lastname: Ogino
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Hisamatsu
authors.forename: Shoshu
authors.initials: S
authors.lastname: Mitsuyama
authors.forename: Hajime
authors.initials: H
authors.lastname: Abe
authors.forename: Shiro
authors.initials: S
authors.lastname: Tanaka
authors.forename: Takuhiro
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ohashi
mesh_terms: D000077384:Anastrozole; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D017024:Chemotherapy, Adjuvant; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007564:Japan; D053208:Kaplan-Meier Estimate; D009367:Neoplasm Staging; D009570:Nitriles / Q000008:administration & dosage* / Q000009:adverse effects; D017698:Postmenopause; D013629:Tamoxifen / Q000008:administration & dosage* / Q000009:adverse effects; D014230:Triazoles / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D009570:Nitriles; D014230:Triazoles; D013629:Tamoxifen; D000077384:Anastrozole