A randomized trial of two dose levels of cyclophosphamide, methotrexate, and fluorouracil chemotherapy for patients with metastatic breast cancer

Abstract

This study was designed to assess the role of dosage of chemotherapy for treatment of metastatic breast cancer. One hundred thirty-three patients without prior chemotherapy for metastatic disease were randomly allocated to receive two different dose levels of cyclophosphamide (C), methotrexate (M), and fluorouracil (F), administered intravenously (IV) every 3 weeks. Patients were stratified by sites of disease (visceral, bone, or soft-tissue dominant) and by interval from primary surgery to first recurrence. Doses on the higher-dose arm were 600 mg/m2 (C,F) and 40 mg/m2 (M) with escalation if possible; doses on the lower-dose arm were 300 mg/m2 (C,F) and 20 mg/m2 (M) without escalation. Patients who failed to respond to lower-dose CMF were crossed over to the higher-dose arm. Patients randomized to the higher-dose arm had longer survival measured from initiation of chemotherapy (median survival, 15.6 months v 12.8 months, P = .026 by log-rank test), but the effect of dose was of borderline significance (P approximately 0.12) when adjusted for a chance imbalance between the two arms in the time from first relapse to randomization, using the Cox proportional hazards model. Response rates (International Union Against Cancer [UICC] criteria) for patients with measurable disease were higher-dose arm: 16/53 (30%) and lower-dose arm: 6/53 (11%), (P = .03). Only one of 37 patients responded on crossover from the lower- to the higher-dose arm. Patients experienced more vomiting, myelosuppression, conjunctivitis, and alopecia when receiving higher doses of chemotherapy. A series of 34 linear analogue self-assessment scales were used to make detailed quality of life assessments on a subset of 49 patients. These scales confirmed greater toxicity in the immediate posttreatment period, but also a trend to improvement in general health and some disease-related indices, in patients receiving higher-dose chemotherapy. This trial suggests that better palliation is achieved by using full-dose chemotherapy.