Intermediate dose single agent cyclophosphamide chemotherapy of advanced breast cancer.

Twenty-one evaluable patients with metastatic breast cancer received three pulses of intravenous cyclophosphamide, escalating from 1.5 g/m2 to 2.5 g/m2 in the second and third courses. There were eight partial remissions (34.7%), but most were of short duration. All responding patients had soft tissue or nodal disease, but additional sites of response were bone (three cases), liver and lung (one case each). Marked leucopaenia (median WBC 0.7 X 10(9)/L) occurred 10-12 days after the higher doses (2.5 g/m2) and was associated with nine episodes of severe infection in five patients. Marked vomiting and anorexia led to significant weight loss (mean 4.5 kg) in half the patients, and alopecia was universal. In metastatic breast cancer cyclophosphamide seems to have a shallow dose response curve and high intermittent dosage seems to have no advantage over chronic daily administration.