Background: Metronomic chemotherapy (MC) has shown efficacy in patients with metastatic breast cancer (MBC). We therefore tested the efficacy and toxicity of MC in pretreated MBC.
Patients and methods: This prospective phase II study included 50 patients with heavily pretreated MBC who received MC in the form of continuous oral cyclophosphamide 50 mg/day and oral methotrexate 2.5 mg twice per day on days 1 and 2 every week. The primary end point was progression-free survival (PFS), whereas the secondary end points were response rate, overall survival (OS), and safety.
Results: Forty-eight patients were assessed. One patient achieved complete response and 10 patients had partial response, whereas 19 patients had stable disease. The median PFS was 5 months, whereas the median OS was 7 months. Patients with negative progesterone receptors, Eastern Cooperative Oncology Group performance status (PS) 1, achieving response, and those who developed leucopenia, neutropenia, and anemia had significant prolonged PFS, whereas patients with early stage at presentation, receiving < 5 previous treatment lines, achieving response, and experiencing anemia with MC had significant superior OS. In multivariate analysis, achieving response, PS 1, a longer time interval from initial diagnosis until starting MC, and anemia were independent prognostic factors for longer PFS. Initial stage at presentation, number of previous treatment lines, and response were independent prognostic factors for OS.
Conclusions: MC is an attractive treatment approach that is effective and less toxic. There are certain groups of patients who seem to benefit more, especially those who experienced toxicity with treatment. Larger trials are warranted to assess this approach early in the course of the disease and with other more active agents.
Keywords: Benefit; MBC; Response; Safety; Survival.
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