Although data regarding the frequency of the prophylactic use of long‐acting G‐CSF between the two periods was not available in our study, there were no significant differences in the use of conventional G‐CSF (33.5% vs. 33.3%), any grades of neutropenia (40.5% vs. 34.9%; p = 0.101), and febrile neutropenia (14.1% vs. 13.7%; p = 0.854) between the pre‐reimbursement and post‐reimbursement group in breast cancer patients. Here, CSF3 is linked to Decreased total neutrophil count.