Extended adjuvant therapy with anastrozole among postmenopausal breast cancer patients: results from the randomized Austrian Breast and

Five years of adjuvant tamoxifen has been the standard endocrine treatment for early-stage breast cancer for several decades. Adjuvant endocrine therapy following primary surgery for breast cancer reduces the risk of recurrence and increases overall survival beyond the period of treatment for women with estrogen receptor (ER) -positive disease ( 1 ). Mature meta-analysis data on 15-year recurrence and breast cancer mortality probabilities demonstrate substantial and persistent benefits of receiving adjuvant tamoxifen compared with no adjuvant treatment ( 1 ). Most of the effect of adjuvant tamoxifen on recurrence is seen during the first 5 years after surgery, when tamoxifen is generally still administered, with gains in recurrence-free survival of 11.4%. However, many women who are treated with 5 years of adjuvant tamoxifen still develop recurrent disease, and most of the effect of adjuvant tamoxifen on breast cancer mortality occurs after the fifth year after surgery