The Patterns of Filgrastim Uses in Breast Cancer Patients Receiving Chemotherapy

항암화학요법을 받은 유방암환자에서의 Filgrastim사용 현황

Filgrastim is used as an indispensable adjuvant drug to reduce the degree and duration of chemotherapy-induced neutropenia. The purpose of this research is to study the use of filgrastim by reviewing retrospective medical records of breast cancer patients who have been treated by filgtastim in the National Cancer Center. 84 patients have received 323 cycles of chemotherapy, of which 134 cycles were treated by filgrastim $(41.5\%)$. Among those 134 cycles, 34 were for prophylaxis $(21.6\%)$, and 100 for treatment of neutropenia $(74.6\%)$. The frequence of filgrastim usage was more than $50\%$ in frequency with regimens containing docetaxel. For prophylaxis, the median of filgrastim initiation was measured on the day of chemotherapy (-3rd-13th). For the treatment, on the other hand, the median appeared on the 9th day (4th-2lst) after chemotherapy, which showed very wide distribution. Time to filgrastim initiation ranged between the 7th and the 9th day after chemotherapy in docetaxel+doxorubicin combination regimen and docetaxel single regimen, whereas it showed after the 10th day in doxorubicin+cyclophosphamide combination regimens. For the treatment, 48 out of 61 patients $(73.8\%)$ in 63 cycles have experienced fever, had to visit the emergency room, required hospitalization, caused infection, transfusion, dosage reduction and schedule changes in spite of using filgrastim with chemotherapy. For prophylaxis, 11 out of 19 patients $(17.9\%)$ in 11 cycles have experienced the same results. In conclusion, the guideline of time to the initiation and the last is required for cost-effective administration of filgrastim because of the difference occurring ANC nadir, the severity and duration of neutropenia by chemotherapy regimens.