Second-Line Chemotherapy with Mitoxantrone as a Single Agent in Metastatic Breast Cancer

Summary

Ninety-three evaluable patients with metastatic breast cancer previously treated with chemotherapy, received mitoxantrone as a single agent (14 mg/m², by rapid intravenous infusion, once every 3 weeks). Patients received a median of 7 courses (range 2 to 18), with a mean cumulative total dose of 133 mg (range 36 to 342). A complete response (CR) was achieved in 2 patients (2%). Partial response (PR) was observed in 23 patients (25%). The overall response rate (CR + PR) was thus 27%, with a median duration of 9 months (range 3 to 18). Responses were observed in all metastatic sites, except for brain and peritoneum. Stabilization (S) occurred in 26 patients (28%). The remaining 42 patients (45%) showed clear progression of their metastatic disease while on therapy. The actuarial 24-month survival for the whole group was 13%, increasing to 29% in responders (CR + PR), as compared with only 10% for non- responders (S + P; P<0.0001). Mitoxantrone was generally well tolerated; nausea, vomiting and hair loss were mild. Nine out of 625 treatment cycles resulted in leukopenic fever with uneventful recovery. All patients had serial MUGA scans; 3 patients (cumulative total doses of 200, 250 and 342 mg, respectively) developed a significant drop in the left ventriculur ejection fraction. Clinical evidence of congestive heart failure was observed in one patient who had received prior doxorubicin-based adjuvant chemotherapy. Mitoxantrone seems to be as effective as other drugs given singly or in combination as second-line chemotherapy in patients with metastatic breast cancer. Its low morbidity makes its use attractive in this setting.