Cyclophosphamide, Methotrexate, and 5-Fluorouracil as Palliative Treatment for Heavily Pretreated Patients with Metastatic Breast Cancer: A Multicenter Retrospective Analysis.

Purpose: This study aimed to evaluate the efficacy and safety of cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) chemotherapy beyond standard treatment for anthracycline-and taxane-pretreated metastatic breast cancer (MBC). Methods: We consecutively enrolled 158 MBC patients who underwent CMF chemotherapy in a palliative setting at two academic hospitals in Korea between 2002 and 2016. Results: The median age of the 158 enrolled patients was 51 years (range, 30-77 years). The enrolled patients were treated with a median of 5 lines of systemic treatment (range, 2-11) before CMF therapy, and the median time from diagnosis of MBC to CMF administration was 36.0 months (range, 7.1-146.7 months). The median number of cycles of CMF treatment was 3 (range, 1-19), and the relative dose intensity was 90.4%. The toxicity profile was mild, with an observed 3.1% of grade 2 and 5.0% of grade 3/4 neutropenia. Among 147 patients (93.0%) whose response to CMF was evaluated, the response rate was 10.9% (16/147), with complete response (CR) in one and partial response (PR) in 15. In addition, the disease control rate (calculated as CR+PR+stable disease) was 44.2% (65/147). The median progression-free survival and overall survival were 3.1 months (95% confidence interval [CI], 2.7-3.6) and 9.4 months (95% CI, 7.1-11.6), respectively. Conclusion: CMF therapy is effective and tolerable as salvage treatment for heavily pretreated MBC.