Treatment of previously treated metastatic breast cancer by mitoxantrone and 48-hour continuous infusion of high-dose 5-FU and leucovorin (MFL): low palliative benefit and high treatment-related toxicity.
For previously treated advanced breast cancer, there is no standard second-line therapy. Combination chemotherapy with mitoxantrone, high-dose 5-fluorouracil (5-FU) and leucovorin (MFL regimen) had been reported as an effective and well tolerated regimen. From October 1993 to November 1995, we treated 13 patients with previously chemotherapy-treated metastatic breast cancer by mitoxantrone, 12 mg/m2, on day 1 and continuous infusion of 5-FU, 3000 mg/m2, together with leucovorin, 300 mg/m2, for 48 h from day 1 to 2. Each course of chemotherapy was given every 4 weeks. Most of these patients had more than two metastatic sites, with lung metastasis predominant. Seven patients had been treated with anthracycline. Seven patients had previously received radiotherapy and seven had received hormone therapy. Median number of courses of MFL regimen given was six and the median cumulative dose of mitoxantrone was 68.35 mg/m2. One patient had complete response, seven had stable disease, none had partial response and five had progressive disease. The overall objective response rate was 7.6%. The median follow-up period was 14 months. Median survival was 16 months. Median progression-free survival was 5 months. A complete responder had relapse-free survival up to 17 months. Major toxicities were cardiotoxicity and leukopenia. Eight patients were dead in the last follow-up; two of them died of treatment-related toxicity. The MFL regimen achieves little palliative benefit and induces severe toxicity at a fairly high rate. Administration of this regimen to breast cancer patients who have been treated by chemotherapy and those with impaired heart function requires careful attention.