Adjuvant endocrine therapy in premenopausal women with breast cancer

Abstract

Breast cancer is the most common malignancy among women worldwide, and a quarter of all breast cancers are diagnosed in premenopausal women. Adjuvant chemotherapy is well established as the therapy of choice for hormone receptor-negative breast cancers. Historically, ovarian ablation substantially inhibited the progression of hormone-responsive breast cancer. Current adjuvant treatment options for premenopausal patients with hormone receptor-positive breast cancer include endocrine therapy and chemotherapy. Pharmacologic ovarian suppression alone has limited efficacy in the adjuvant setting, but it offers good clinical outcomes when combined with tamoxifen or chemotherapy. In recent years, aromatase inhibitors (AIs) have become the endocrine therapy of choice in postmenopausal women with hormone-responsive breast cancer, but their efficacy in the premenopausal setting is yet to be established. However, in a large, phase III randomized study (Austrian Breast and Colorectal Cancer Study Group Trial 12) that matured earlier this year, the combination of ovarian suppression and AI, anastrozole, did not show superior efficacy compared with ovarian suppression plus tamoxifen, but was associated with fewer serious adverse effects in premenopausal women with early stage hormone-responsive breast cancer. Data from ongoing and future trials will help to further define the role of ovarian suppression and AIs in the adjuvant setting for premenopausal breast cancer. © 2009 Copyright © Cambridge University Press 2009.