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Switching of postmenopausal women with endocrine-responsive early breast cancer to anastrozole after 2 years' adjuvant tamoxifen: combined results of ABCSG trial 8 and ARNO 95 trial.
Lancet. 2005 Aug 6-12; 366(9484):455-62.Lct

Abstract

BACKGROUND

Tamoxifen has been the standard adjuvant treatment for postmenopausal women with hormone-responsive early breast cancer for more than 20 years. However, the third-generation aromatase inhibitor anastrozole has proven efficacy and tolerability benefits compared with tamoxifen when used as initial adjuvant therapy. We investigate whether women who have received a period of adjuvant tamoxifen would benefit from being switched to anastrozole.

METHODS

We present a combined analysis of data from two prospective, multicentre, randomised, open-label trials with nearly identical inclusion criteria. Postmenopausal women with hormone-sensitive early breast cancer who had completed 2 years' adjuvant oral tamoxifen (20 or 30 mg daily) were randomised to receive 1 mg oral anastrozole (n=1618) or 20 or 30 mg tamoxifen (n=1606) daily for the remainder of their adjuvant therapy. The primary endpoint was event-free survival, with an event defined as local or distant metastasis, or contralateral breast cancer. Analysis was by intention to treat.

FINDINGS

3224 patients were included in analyses. At a median follow-up of 28 months, we noted a 40% decrease in the risk for an event in the anastrozole group as compared with the tamoxifen group (67 events with anastrozole vs 110 with tamoxifen, hazard ratio 0.60, 95% CI 0.44-0.81, p=0.0009). Both study treatments were well tolerated. There were significantly more fractures (p=0.015) and significantly fewer thromboses (p=0.034) in patients treated with anastrozole than in those on tamoxifen.

INTERPRETATION

These data lend support to a switch from tamoxifen to anastrozole in patients who have completed 2 years' adjuvant tamoxifen.

Authors+Show Affiliations

Austrian Breast and Colorectal Cancer Study Group (ABCSG), Vienna Medical University, Vienna General Hospital, Waehringer Guertel 18-20, Vienna A-1090, Austria. raimund.jakesz@meduniwien.ac.atNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Multicenter Study
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16084253

Citation

Jakesz, Raimund, et al. "Switching of Postmenopausal Women With Endocrine-responsive Early Breast Cancer to Anastrozole After 2 Years' Adjuvant Tamoxifen: Combined Results of ABCSG Trial 8 and ARNO 95 Trial." Lancet (London, England), vol. 366, no. 9484, 2005, pp. 455-62.
Jakesz R, Jonat W, Gnant M, et al. Switching of postmenopausal women with endocrine-responsive early breast cancer to anastrozole after 2 years' adjuvant tamoxifen: combined results of ABCSG trial 8 and ARNO 95 trial. Lancet. 2005;366(9484):455-62.
Jakesz, R., Jonat, W., Gnant, M., Mittlboeck, M., Greil, R., Tausch, C., Hilfrich, J., Kwasny, W., Menzel, C., Samonigg, H., Seifert, M., Gademann, G., Kaufmann, M., & Wolfgang, J. (2005). Switching of postmenopausal women with endocrine-responsive early breast cancer to anastrozole after 2 years' adjuvant tamoxifen: combined results of ABCSG trial 8 and ARNO 95 trial. Lancet (London, England), 366(9484), 455-62.
Jakesz R, et al. Switching of Postmenopausal Women With Endocrine-responsive Early Breast Cancer to Anastrozole After 2 Years' Adjuvant Tamoxifen: Combined Results of ABCSG Trial 8 and ARNO 95 Trial. Lancet. 2005 Aug 6-12;366(9484):455-62. PubMed PMID: 16084253.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Switching of postmenopausal women with endocrine-responsive early breast cancer to anastrozole after 2 years' adjuvant tamoxifen: combined results of ABCSG trial 8 and ARNO 95 trial. AU - Jakesz,Raimund, AU - Jonat,Walter, AU - Gnant,Michael, AU - Mittlboeck,Martina, AU - Greil,Richard, AU - Tausch,Christoph, AU - Hilfrich,Joern, AU - Kwasny,Werner, AU - Menzel,Christian, AU - Samonigg,Hellmut, AU - Seifert,Michael, AU - Gademann,Guenther, AU - Kaufmann,Manfred, AU - Wolfgang,Johann, AU - ,, PY - 2005/8/9/pubmed PY - 2005/10/7/medline PY - 2005/8/9/entrez SP - 455 EP - 62 JF - Lancet (London, England) JO - Lancet VL - 366 IS - 9484 N2 - BACKGROUND: Tamoxifen has been the standard adjuvant treatment for postmenopausal women with hormone-responsive early breast cancer for more than 20 years. However, the third-generation aromatase inhibitor anastrozole has proven efficacy and tolerability benefits compared with tamoxifen when used as initial adjuvant therapy. We investigate whether women who have received a period of adjuvant tamoxifen would benefit from being switched to anastrozole. METHODS: We present a combined analysis of data from two prospective, multicentre, randomised, open-label trials with nearly identical inclusion criteria. Postmenopausal women with hormone-sensitive early breast cancer who had completed 2 years' adjuvant oral tamoxifen (20 or 30 mg daily) were randomised to receive 1 mg oral anastrozole (n=1618) or 20 or 30 mg tamoxifen (n=1606) daily for the remainder of their adjuvant therapy. The primary endpoint was event-free survival, with an event defined as local or distant metastasis, or contralateral breast cancer. Analysis was by intention to treat. FINDINGS: 3224 patients were included in analyses. At a median follow-up of 28 months, we noted a 40% decrease in the risk for an event in the anastrozole group as compared with the tamoxifen group (67 events with anastrozole vs 110 with tamoxifen, hazard ratio 0.60, 95% CI 0.44-0.81, p=0.0009). Both study treatments were well tolerated. There were significantly more fractures (p=0.015) and significantly fewer thromboses (p=0.034) in patients treated with anastrozole than in those on tamoxifen. INTERPRETATION: These data lend support to a switch from tamoxifen to anastrozole in patients who have completed 2 years' adjuvant tamoxifen. SN - 1474-547X UR - https://www.unboundmedicine.com/medline/citation/16084253/Switching_of_postmenopausal_women_with_endocrine_responsive_early_breast_cancer_to_anastrozole_after_2_years'_adjuvant_tamoxifen:_combined_results_of_ABCSG_trial_8_and_ARNO_95_trial_ DB - PRIME DP - Unbound Medicine ER -