Prophylactic administration of granulocyte colony-stimulating factor in epirubicin and cyclophosphamide chemotherapy for Japanese breast cancer patients: a retrospective study

Purpose: Epirubicin and cyclophosphamide (EC) therapy, a major chemotherapy for patients with early-stage breast cancer, has a low risk (< 10%) of febrile neutropenia (FN). However, data used in reports on the incidence rate of FN were derived primarily from non-Asian populations. In this study, we investigated the FN incidence rate using EC therapy among Japanese patients with breast cancer and evaluated the significance of prophylactic administration of granulocyte colony-stimulating factor (G-CSF). Methods: We evaluated medical records of patients with early-stage breast cancer who had been treated with EC therapy as neoadjuvant or adjuvant therapy between November 2014 and July 2018. Results: The incidence rate of FN was 23.9%. In patients who received G-CSF as primary prophylaxis, FN expression was completely suppressed. The incidence rate of severe leucopenia/neutropenia, emergency hospitalization, and the use of antimicrobial agents were low in patients receiving primary prophylaxis with G-CSF compared with those not receiving G-CSF (27.3% vs. 64.8%, 9.1% vs. 27.3%, and 27.3% vs. 71.6%, respectively). Furthermore, in all patients who received primary prophylaxis with G-CSF, a relative dose intensity > 85% using EC therapy was maintained. Conclusion: The incidence of FN in EC therapy among Japanese patients was higher than expected, EC therapy appears to be a high-risk chemotherapy for FN, and prophylactic administration of G-CSF is recommended. Maintaining high therapeutic intensity is associated with a positive prognosis for patients with early breast cancer, and prophylactic administration of G-CSF is likely to be beneficial in treatment involving EC therapy.