OUTLINE: This is a randomized, double-blind, placebo-controlled, multicenter study. Patients are stratified according to receptor status (positive vs unknown), lymph node status (negative vs positive vs unknown), prior adjuvant chemotherapy (yes vs no), interval between last dose of aromatase inhibitor therapy and randomization (< 6 months vs 6 months-2 years), and duration of prior tamoxifen use (0 years vs < 2 years vs 2-4.5 years vs > 4.5 years). Patients are randomized to 1 of 2 treatment arms.