Comparison of adjuvant ED and EC-D regimens in operable breast invasive ductal carcinoma

In China, the adjuvant epirubicin and docetaxel (ED) regimen is widely used as a substitute for the epirubicin and cyclophosphamide followed by docetaxel (EC-D) regimen in patients with operable breast cancer. However, their equivalence has not yet been demonstrated. This retrospective study compared these two adjuvant regimens as regards feasibility, safety and efficacy. Data on consecutive patients who received either ED (70/75 mg/m² every 3 weeks for 6 cycles) or EC-D (70/600 mg/m² epirubicin/cyclophosphamide followed by 75 mg/m² docetaxel every 3 weeks for 4 cycles each) as their adjuvant chemotherapy in our center from January 2009 to January 2014, were analyzed. A total of 374 patients was enrolled, among whom 250 patients received the ED regimen, and 124 patients received the EC-D regimen. The overall median follow-up time was 38.6 months. In total, 90 and 94.4% of patients in the ED and EC-D groups, respectively, completed full cycles of chemotherapy (P=0.174). There was no difference in efficacy in terms of disease-free survival (DFS) and overall survival (OS) (DFS, P=0.919; OS, P=0.069). The incidence of neutropenia in the ED group was similar to that in the EC-D group (81.2 vs. 78.9%, P=0.660) with a similar utilization rate of granulocyte-colony stimulating factor (G-CSF; 76.9 vs. 75.2%, P=0.850). However, grade 3/4 gastrointestinal reactions were more frequently observed in the patients who received the EC-D regimen (42.0 vs. 29.2%, P=0.058). The findings of our study indicate that with similar feasibility, safety and mid-term efficacy, the adjuvant ED regimen for 6 cycles may be an alternative to the EC-D regimen in operable breast cancer.