Mitoxantrone in advanced breast cancer--a phase II study with special attention to cardiotoxicity.

Thirty-four patients with advanced breast cancer, who had not received previous chemotherapy for metastatic disease, were treated with mitoxantrone 14 mg/m2 i.v. every 21 days. Eleven of 33 evaluable patients (33%) achieved a partial response; there were no complete responders. Before commencing mitoxantrone, and 3-monthly thereafter, radionuclide assessment of ventricular performance was obtained at rest and in response to stress. Ten patients showed a deterioration in ejection fraction, two of whom developed congestive cardiac failure. Dose-limiting toxicity was myelosuppression. Nausea and vomiting were generally mild and transient. Alopecia was minimal in most patients. Mitoxantrone is an active, well-tolerated new drug in the treatment of advanced breast cancer, but cardiotoxicity may occur in a proportion of patients. Further investigation is required to determine the precise nature, incidence and prognosis of cardiotoxicity encountered with mitoxantrone.