Adjuvant chemotherapy of breast cancer. Many women will not be cured of breast cancer by even the best early detection and surgical techniques because of micrometastases present at diagnosis. Adjuvant therapy has extended the disease-free interval for most patients and lengthens overall survival for many. Combination chemotherapy has become the standard form of adjuvant treatment for premenopausal women with breast cancer and positive lymph nodes after primary therapy. With minimal toxicity, disease-free and overall survival are improved. Results are less impressive or less clear-cut for postmenopausal women or any woman with negative lymph nodes. Long-term toxicities of adjuvant chemotherapy may include second malignancies and cardiac dysfunction. Although these complications probably are rare, they must be considered seriously when weighing chemotherapy for patients in whom its benefits may be slight. Innovations likely to become standard in adjuvant therapy decision making include risk assessment with new prognostic indicators (growth fraction, oncogene expression) and investigation of dose intensification using bone marrow growth factors and autologous stem-cell support. 