Efficacy of Adjuvant Chemotherapy in High-Risk Node-Negative Breast Cancer

Abstract
We randomly assigned 536 women who had undergone either a modified radical mastectomy or a total mastectomy with low axillary-node dissection for potentially curable breast carcinoma to receive adjuvant chemotherapy or no-treatment observation. The patients were considered at high risk for recurrence because they had either an estrogen-receptor–negative tumor of any size or an estrogen-receptor–positive tumor at least 3 cm in diameter with no histopathological evidence of axillary-node involvement. The chemotherapy consisted of six four-week cycles of cyclophosphamide (100 mg per square meter of body-surface area orally on days 1 through 14), methotrexate (40 mg per square meter intravenously on days 1 and 8), fluorouracil (600 mg per square meter intravenously on days 1 and 8), and prednisone (40 mg per square meter orally on days 1 through 14). Treatments were balanced with respect to patients' characteristics. The analysis included 406 eligible patients who were entered in the study before October 1, 1987. The overall disease-free survival among patients treated with the four-drug regimen was 84 percent, as compared with 69 percent for the control group, at a median follow-up of three years (P = 0.0001). A treatment benefit was also observed in premenopausal and postmenopausal patients as well as in patients with estrogen-receptor–positive or with estrogen-receptor–negative tumors. Severe or life-threatening hematologic toxicity was encountered in 33 percent of the treated patients, with one death.