[Mitoxantrone in the primary treatment of metastasizing breast cancer]

25 females (57.7 +/- 11.1 years) and 1 male (71 years) with histologically verified metastasizing breast cancer were submitted to mitoxantrone therapy. Secondary tumours were found in following organ systems: bone: 19 cases; lung: 13 cases; liver: 6 cases; skin: 5 cases; locoregional and nodal: 5 cases; brain: 1 case. All patients showed normal bone marrow and heart function before commencement of treatment. Mitoxantrone was given in form of a 30-minute infusion at a dosage of 14 mg/m2. In 4 patients dosage was increased to 20 mg/m2. Treatment cycles were repeated every 3 weeks according to peripheral blood counts. All patients were cardiologically monitored throughout the study by means of electrocardiogram, systolic time interval measurement and radionuclide angiography. The mean observation period was 169 +/- 98 days. The response of the patients was as follows: 1 complete remission, 5 partial remissions, 4 unchanged disease and 16 progressive disease. Side effects were normally mild; only nausea, leucopenia and moderate hair loss were of clinical relevance. Cardiac decompensation was not observed. No significant electrocardiographic alterations were found throughout the study. Results of systolic time interval measurements (PEPI, PEP:LVET) and radionuclide angiography (LVEF) gave evidence of moderate depression of heart function. In view of the optimal benefit/risk ratio of mitoxantrone this drug could be used in combined modality treatment schedules in metastasizing breast cancer.