Adjuvant cyclophosphamide, methotrexate, and fluorouracil in patients with axillary node-positive breast cancer: an update of the Guy's/Manchester trial. Between 1976 and 1985, 391 patients (202 premenopausal, 189 postmenopausal) with operable breast cancer and positive axillary lymph nodes were randomized after total mastectomy and axillary clearance to receive cyclophosphamide, methotrexate, and fluorouracil (CMF) (n = 193) or no adjuvant therapy (n = 198). After a median follow-up of 8 years, both relapse-free survival (RFS) and survival (S) were significantly prolonged in premenopausal patients receiving CMF (RFS, P less than .001; S, P = .003). Treatment with CMF resulted in a significant improvement in RFS in premenopausal patients both with steroid receptor-positive and steroid receptor-negative tumors and also in subgroups of premenopausal patients defined by the number of axillary nodes involved. Premenopausal patients who developed permanent amenorrhea following CMF had a significantly better RFS than those who continued to menstruate. Induction of amenorrhea following CMF was related to age, with almost all patients over 40 years becoming amenorrheic. For patients less than or equal to 40 years, development of amenorrhea following CMF did not influence outcome. No difference was detected between control and CMF groups (RFS, P = .9; S, P = .9) in postmenopausal patients nor in any subgroup of these patients. The results of this trial of the efficacy of CMF for improving RFS and S have strengthened with longer follow-up. 