Febrile neutropenia and role of prophylactic granulocyte colony-stimulating factor in docetaxel and cyclophosphamide chemotherapy for breast cancer

Purpose Febrile neutropenia (FN) incidence during docetaxel and cyclophosphamide (TC) chemotherapy, known as a high-risk regimen, differs among countries. The role of prophylactic granulocyte colony-stimulating factor (G-CSF) in FN is unclear. This study aimed to investigate FN frequency and relative dose intensity (RDI) of TC chemotherapy in patients with breast cancer and identify the correct population requiring prophylactic G-CSF. Methods In total, 205 patients with breast cancer were scheduled for TC chemotherapy (docetaxel/cyclophosphamide 75/600 mg/m 2 , every 3 weeks, 4 cycles) as adjuvant chemotherapy. Trastuzumab (8 mg/kg; continued with 6 mg/kg) was administrated intravenously for human epidermal growth factor receptor 2 (HER2)-positive cancer. Fifty-five patients received primary prophylactic measures (G-CSF: 20 and antibiotics: 35). We investigated the frequency of FN and hospitalization, RDI, and the factors related to FN, adverse events, hospitalization, and RDI. Results FN occurred in 70 patients (35.7%). FN incidence was noted in 41.1% without any prophylactic measures and in 5.0% with prophylactic G-CSF. In multivariate analysis, the independent risk factors of FN were older age (≥ 60 years, P = 0.017) and without primary prophylactic G-CSF ( P = 0.011). Eleven patients (5.6%) were hospitalized of which 8 (72.7%) were elderly. The median RDIs of docetaxel and cyclophosphamide were 96.7% and 99.7%, respectively. Conclusion FN frequency during TC chemotherapy was high, and primary prophylactic G-CSF reduced FN incidence. Primary prophylactic G-CSF is an effective therapy for preventing FN during TC chemotherapy. However, prophylactic G-CSF should be considered for elderly patients based on the low hospitalization rate and the high RDI.