Previous studies have shown that the protracted infusion of adriamycin (ADM) by the ambulatory delivery system can significantly decrease both the cardiac and hematological toxicity caused by intermittent bolus administration. We treated 27 patients with metastatic breast cancer who had been heavily pretreated with regimens including ADM. Treatment consisted of 15- or 25-day courses of ADM at a mean dose of 3.8 mg/m2 (2.2-4.5 mg/m2) infused by programmable portable pump. Early cardiac toxicity was detected by echocardiography-Doppler. Two-dimensional echocardiography made possible the detection of interventricular septum hypokinetics, an early sign of a decrease of systolic function of the left ventricle. Despite the very high cumulative dose of ADM (mean dose 777.79 mg/m2, range 282-1647 mg/m2) received by these patients, no clinical heart failure was observed. Most frequently observed complications were oral mucositis, Grade 2 and 3 (10 patients), and complications related to the drug delivery system (15/137 courses). Hematological toxicity was minimal. Seven Grade 2 and five Grade 3 (but no Grade 4) alopecia were observed. Objective response was obtained in four of 24 patients (17%) evaluated for response, (only 21 were fully evaluable): one complete response and three partial responses (duration: 6.6, 7 and 11 months, respectively). Stabilization was seen in 14 patients lasting three to 26 months. The performance status and symptoms of nine of the patients (37%) was significantly improved. Our results show that continuous infusion of ADM is well tolerated and provides palliation to patients with metastatic breast cancer. It merits a trial as first-line treatment.