Effectiveness of switching from adjuvant tamoxifen to anastrozole in postmenopausal women with hormone-sensitive early-stage breast cancer: a meta-analysis

Walter Jonat, Michael Gnant, Francesco Boccardo, Manfred Kaufmann, Alessandra Rubagotti, Ivan Zuna, Mike Greenwood, Raimund Jakesz

Research output: Contribution to journalArticlepeer-review

Abstract

Background: For more than 20 years, tamoxifen has been the mainstay of adjuvant endocrine therapy for women with hormone-sensitive early-stage breast cancer. However, not only does tamoxifen have potential side-effects such as an increased risk of endometrial cancer and thromboembolic events, but patients can also develop resistance to the drug. We aimed to investigate whether switching treatment of postmenopausal women with such breast cancer to anastrozole after 2-3 years of tamoxifen would be more effective than continuing on tamoxifen for a total of 5 years. Methods: We did a meta-analysis of three clinical trials-the Austrian Breast and Colorectal Cancer Study Group (ABCSG 8), Arimidex-Nolvadex (ARNO 95), and the Italian Tamoxifen Anastrozole (ITA) studies-in which postmenopausal women with histologically confirmed, hormone-sensitive early-stage breast cancer were randomised to 1 mg/day anastrozole (n=2009) after 2-3 years of tamoxifen treatment or to continued 20 or 30 mg/day tamoxifen (n=1997). We analysed the data with a stratified Cox proportional hazards model with the covariates of age, tumour size, nodal status, grade, surgery, and chemotherapy. Findings: Patients who switched to anastrozole had fewer disease recurrences (92 vs 159) and deaths (66 vs 90) than did those who remained on tamoxifen, resulting in significant improvements in disease-free survival (hazard ratiro 0·59 [95% CI 0·48-0·74]; p

Original languageEnglish
Pages (from-to)991-996
Number of pages6
JournalThe Lancet Oncology
Volume7
Issue number12
DOIs
Publication statusPublished - Dec 2006

ASJC Scopus subject areas

  • Oncology

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