Aims and background: The combination of mitoxantrone plus leucovorin/fluorouracil in heavily pretreated patients with advanced breast cancer has shown significant activity and extremely good tolerability. The aim of this study was to evaluate the activity of this combination in patients not previously submitted to chemotherapy.
Methods: From May 1993 to December 1995 we treated 80 patients with advanced breast cancer with a combination of mitoxantrone, l-leucovorin and 5-fluorouracil. All patients had histologically or cytologically proven breast cancer, WHO performance status 0-3, normal hematological parameters and normal serum bilirubin. Prior chemotherapy for metastatic disease was not allowed, whereas adjuvant CMF (cyclophosphamide, methotrexate and 5-fluorouracil) or adjuvant anthracycline (doxorubicin or epirubicin) therapy was allowed; a single prior hormone treatment was permitted. Chemotherapy consisted of mitoxantrone 12 mg/m2 i.v. day 1, l-leucovorin 150 mg/m2 i.v. days 1, 2 and 3 and 5-fluorouracil 350 mg/m2 i.v. days 1, 2 and 3. The courses were repeated every 3 weeks.
Results: Objective response (CR + PR) was observed in 46/80 (57%) patients (95% CI, 46%-68%). Complete response (CR) was observed in 21/80 cases (26%). Response was observed in 14/24 (58%) patients with soft tissues as the dominant site of disease, in 22/34 (65%) patients with visceral involvement and in 10/22 (45%) of those with bone as the dominant site of disease. The median duration of response and survival was 9 months (range, 3-16) and 22 months (range, 2-48+), respectively. Toxicity was very manageable, with grade 4 leukopenia and thrombocytopenia in 6/80 (7.5%) and 1/80 (1.25%) patients, respectively, and negligible non-hematological toxicity.
Conclusions: The combination of mitoxantrone, 5-fluorouracil and high-dose l-leucovorin is a safe and effective regimen for first-line treatment of advanced breast cancer.