OUTLINE: This is a double-blind, multicenter, placebo-controlled, randomized study. Patients are stratified according to pathologic nodal status (negative vs positive), adjuvant tamoxifen citrate therapy (yes vs no), and lowest bone mineral density T score for lumbosacral spine, total hip, or femoral neck (> -2.0 vs ≤ -2.0 standard deviation). Patients are randomized to 1 of 2 treatment arms.