title: Anastrozole versus tamoxifen as adjuvant therapy for Japanese postmenopausal patients with hormone-responsive breast cancer: efficacy results of long-term follow-up data from the N-SAS BC 03 trial.
abstract: Aromatase inhibitors are superior to tamoxifen as adjuvant therapy in postmenopausal patients with hormone-responsive breast cancer. We report the follow-up efficacy results from the N-SAS BC 03 trial (UMIN CTRID: C000000056) where anastrozole was compared with tamoxifen as adjuvant therapy in postmenopausal Japanese patients with hormone-responsive early breast cancer. The full analysis set contained 696 patients (anastrozole arm, n = 345; tamoxifen arm, n = 351). The log-rank test was used to compare the two groups in terms of disease-free survival (DFS) and relapse-free survival (RFS); Kaplan-Meier estimates were calculated. The treatment effects were estimated by Cox's proportional hazards model. To examine time-varying effect of hazard ratios, we estimated time-varying hazard ratios at time t [HR(t)] using data from time t up to 12 months. After a median follow-up of 98.5 months, hazard ratios (95% CIs) were 0.90 (0.65-1.24; log-rank p = 0.526) for DFS and 0.83 (0.56-1.23; log-rank p = 0.344) for RFS. Hazard ratios (95% CIs) for DFS and RFS up to 36 months were 0.69 (0.40-1.17) and 0.54 (0.27-1.06) and those after 36 months were 1.06 (0.70-1.59) and 1.05 (0.64-1.73), respectively. Time-varying hazard ratios for both DFS and RFS showed that hazard ratios were initially in favor of anastrozole and approached 1.0 at around 36 months. Superior efficacy of anastrozole to tamoxifen suggested by the initial analysis was not confirmed in the present analysis after a long-term follow-up period. Advantage of anastrozole was the greatest immediately after switching from tamoxifen and then decreased thereafter.
authors.affiliation: Breast Center, Aihara Hospital, 3-4-30, Makiochi, Minoh, Osaka, 562-0004, Japan, aiharat@aiharabreast.com.
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Aihara
authors.forename: Isao
authors.initials: I
authors.lastname: Yokota
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Hozumi
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Aogi
authors.forename: Hiroji
authors.initials: H
authors.lastname: Iwata
authors.forename: Motoshi
authors.initials: M
authors.lastname: Tamura
authors.forename: Atsushi
authors.initials: A
authors.lastname: Fukuuchi
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Makino
authors.forename: Ryungsa
authors.initials: R
authors.lastname: Kim
authors.forename: Masashi
authors.initials: M
authors.lastname: Andoh
authors.forename: Koichiro
authors.initials: K
authors.lastname: Tsugawa
authors.forename: Shinji
authors.initials: S
authors.lastname: Ohno
authors.forename: Takuhiro
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ohashi
authors.forename: Toru
authors.initials: T
authors.lastname: Watanabe
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Takatsuka
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Mukai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000077384:Anastrozole; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D009367:Neoplasm Staging; D009570:Nitriles / Q000627:therapeutic use*; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D015996:Survival Rate; D013629:Tamoxifen / Q000627:therapeutic use*; D014230:Triazoles / Q000627:therapeutic use*
chemical_list: D000077384:Anastrozole; D018931:Antineoplastic Agents, Hormonal; D014408:Biomarkers, Tumor; D009570:Nitriles; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D013629:Tamoxifen; D014230:Triazoles; C508053:ERBB2 protein, human