[Investigation of the Changes in Blood Cell Components following the Administration of Pegfilgrastim in Neo-Adjuvant and Adjuvant FEC Chemotherapy for Breast Cancer].

Perioperative fluorouracil, epirubicin and cyclophosphamide(FEC)therapy is a standard treatment for breast cancer. However, more than 20% of patients with breast cancer who undergo FEC therapy experience febrile neutropenia(FN), for which pegfilgrastim is commonly recommended as primary prophylaxis. Although the efficacy and safety of pegfilgrastim were verified at the time of drug approval, there are still no reports on its long-term safety. In this study, we assessed the long-term safety of pegfilgrastim and changes in blood cell components, further assessing the incidence of FN. There were no significant differences in the leukocyte count, neutrophil count, lymphocyte count, hemoglobin concentration, or platelet count with or without the use of pegfilgrastim at 1 year. No long-term effects of pegfilgrastim on blood cell components were observed. The incidence of FN was 6.5% with pegfilgrastim administration and 22.8% without pegfilgrastim administration(p=0.020). Primary prophylaxis with pegfilgrastim can reduce the incidence of FN and can be safely used for 1 year after initial administration in patients with breast cancer undergoing chemotherapy.