Two intensive chemotherapy regimens CFPMV (Cytoxan [cyclophosphamide], 5-fluorouracil, prednisone, methotrexate, vincristine) and CA (Cytoxan, Adriamycin [doxorubicin]) were tested against a moderate regimen, CFP, in a prospective three-arm, randomized study with crossover when relapse or failure occurred, in order to assess whether the response, duration of remission, and survival can be altered by using more intensive regimens as first-line or as rescue therapy. All three regimens were equally effective as initial chemotherapy: CFP 26/46 (57%); CFPMV 31/48 (65%) and CA 26/47 (55%) (P = 0.61) with the least toxicity for the CFP regimen. Median duration of remission were 9.5, 11, and 9 months, respectively. Complete responses were almost identical in all three regimens: 4/46 (9%); 6/48 (12%) and 5/47 (11%) (P = 0.94). CFPMV was an effective regimen as second-line therapy: 11/33 (33%) or third-line therapy: 7/21 (33%). The CA regimen was equally effective as second-line therapy: 8/25 (32%), suggesting that intensive regimens provide an effective rescue therapy, as well in previous responders as in nonresponders. Initial intensive regimens have not substantially altered long-term survival in the whole group of treated patients, Arm II (CFPMV----CA----CFP) 17.6 months; Arm III (CA----CFP----CFPMV) 12.3 months when compared with initial moderate regimens Arm I (CFP----CFPMV----CA) 16.6 months (P = 0.24). The same lack of difference in survival was noticed in responder patients in each arm: Arm II 19.0 months; Arm III 16.0 months versus Arm I 22.0 months (P = 0.13). Our data suggest that a moderate regimen is as effective as more intense regimens for induction therapy in metastatic breast cancer, with less toxicity, preserving the opportunity for an effective rescue therapy with intensive regimens in second or third-line chemotherapy.