Reduction of toxicity by reversing the order of infusion in docetaxel and cyclophosphamide (TC).

Abstract

2576 Background: Although TC (docetaxel 75mg/m2 and cyclophosphamide 600mg/m2, q3w) combination is among the most widely used neoadjuvant/adjuvant chemotherapy for primary breast cancer, allergic reactions including rash and edema are occasionally met. This study aimed to determine whether adverse events (AEs) particularly allergic reactions were more common in TC, docetaxel infused prior to cyclophosphamide compared to reverse TC (rTC), cyclophosphamide infused prior to docetaxel. Methods: Retrospective analysis was done at a single institution in consecutive 85 patients treated with TC or rTC for stage 1-3 breast cancer from 2007 to 2010. TC was used in former 2.5 years and rTC in latter 1.5 years. Dexamethasone was administered to prevent allergic reaction in both. Two tailed Fisher Exact test was used to evaluate the significance of proportional differences in AEs between two regimens according to CTCAE ver.4. Results: Among 85 patients, 50 were in TC and 35 in rTC. Baseline characteristics of two groups were not different. Significant decreases in fatigue (11% vs. 72%), edema (11% vs. 48%), neuropathy (14% vs. 66%), and myalgia (6% vs. 48%) were observed in rTC as compared with TC. There were also decreased incidences of grade 3 and 4 edema (0% vs. 2%), neuropathy (3% vs. 10%), myalgia (0% vs. 2%), and rash (6% vs. 10%) in rTC. All 2 cases who did not complete their treatments were in TC due to rash. Hematologic AEs were not different in 2 regimens. Conclusions: Patients receiving cyclophosphamide infused prior to docetaxel were decreased risk for several toxicities as compared with docetaxel infused prior to cyclophosphamide. The immunosuppressive effects of cyclophosphamide may reduce hypersensitivity reactions with docetaxel by reversing order of infusion.