Efficacy and safety of cyclophosphamide in anthracycline- and taxane-based neoadjuvant chemotherapy in breast cancer: a meta-analysis.

Background: Our study aimed to compare the efficacy and safety of anthracycline plus taxane (AT)-based neoadjuvant chemotherapy (NAC) with or without cyclophosphamide in the treatment of breast cancer.

Methods: We searched PubMed, Embase, Web of Science and the Cochrane Library for randomized controlled studies comparing the efficacy and safety of AT-based NAC with or without cyclophosphamide in breast cancer patients.

Results: Four eligible studies with 2,302 individuals were ultimately included in the quantitative analysis. After applying the AT-based NAC regimen, the overall rates of pathologic complete response (pCR) and breast conserving surgery in all included subjects were 26.5% and 70.6%, respectively. The rates of pCR [risk ratio (RR): 1.35; 95% CI: 0.75, 2.45; P=0.32], breast-conserving surgery (RR: 1.07; 95% CI: 0.97, 1.19; P=0.17) and clinical response (RR: 1.08; 95% CI: 0.97, 1.19; P=0.15) in patients in the cyclophosphamide group were similar to those in the control group. However, participants in the cyclophosphamide group had a lower no clinical response rate than those in the control group (RR: 0.72; 95% CI: 0.60, 0.87; P<0.001). Subjects in the cyclophosphamide group had significantly lower rates of infection (RR: 0.57; 95% CI: 0.41, 0.79; P<0.001) and diarrhea (RR: 0.46; 95% CI: 0.30, 0.68; P<0.001) and higher rates of thrombocytopenia (RR: 3.38; 95% CI: 1.96, 5.84; P<0.001), sensory/motor neuropathy (RR: 1.57; 95% CI: 1.03, 2.39; P=0.03) and nausea/vomiting (RR: 1.51; 95% CI: 1.11, 2.06; P=0.009) than those in the control group.

Conclusions: The AT-based NAC regimen with or without cyclophosphamide had similar clinical outcomes in breast cancer patients. The addition of cyclophosphamide might increase the risks of thrombocytopenia, sensory/motor neuropathy and nausea/vomiting.