OBJECTIVES: I. Compare disease-free survival and overall survival of postmenopausal women with node-positive, estrogen and/or progesterone receptor-positive adenocarcinoma of the breast randomly assigned to postoperative adjuvant treatment with long-term (5 years) tamoxifen vs. CAF (cyclophosphamide/doxorubicin/fluorouracil) plus concurrent and long-term tamoxifen vs. CAF followed by long-term tamoxifen. II. Compare the relative toxicities of these three regimens.