Thirty-three patients with advanced and refractory breast cancer were treated with two mitoxantrone-containing regimens (mitoxantrone plus mitomycin and mitoxantrone plus mitomycin plus methotrexate). All patients had received previous chemotherapy with cyclophosphamide, methotrexate and fluorouracil (CMF); cyclophosphamide, adriamycin and fluorouracil (CAF); or CMF and CAF. Partial response occurred in five patients (15 +/- 12%), stable disease occurred in 15 patients (45 +/- 17%) and progressive disease occurred in 13 patients (40 +/- 17%). The median duration of response was 5 months. The median actuarial survival was 11 months. Toxicity was mild, even in patients who had previously received anthracyclines; generally it was mainly hematological. We thus recommend mitoxantrone-containing regimens as salvage chemotherapy in advanced breast cancer.