 OUTLINE: This is a randomized, double-blind, placebo-controlled study. Patients are stratified according to age 50 years old vs 50-60 years old vs 60 years old, sex, capecitabine dose level 2000 mgday vs 2500 mgday, cancer type breast vs other, and mode of therapy adjuvant including neo-adjuvant therapy vs metastatic disease. Patients are randomized to 1 of 6 treatment arms treatment arms I-IV closed to accrual as of 1024007. 