Background: Chemotherapy-induced febrile neutropaenia (FN) is a common and life-threatening adverse event, which can be largely prevented by the use of granulocyte colony-stimulating factor (G-C SF); G-CSF, however is expensive and not without side effects. Although primary G-CSF prophylaxis is recommended when the risk of FN is >= 20%, it is unclear during which cycles it should be administered. This study assessed and compared the FN incidence in the neo-adjuvant or adjuvant administration of two chemotherapy regimens that are widely used in breast cancer care to provide clinically useful recommendations for G-CSF use. Methods: 221 breast cancer patients were included in this retrospective single-centre study. In total, 181 patients received three cycles of 5-flourouracil, epirubicin, cyclophosphamide (FEC) followed by three cycles of docetaxel (3F-3D) (81.9%); 40 patients received four cycles of doxorubicin, cyclophosphamide (AC) followed by twelve cycles of paclitaxel (4AC-12P) (18.1%). The episodes of FN, extracted from the electronic patient files, were analysed and compared. Results: Overall, FN was identified in 27.8% of patients and occurred significantly more in patients receiving 3F-3D compared to patients receiving 4AC-12P (31.5% versus 10.0%, OR 4.14, 95% CI: 1.14-12.18). Comparison of FN occurrence after first exposure to FEC (6.1%), AC (5.0%), docetaxel (20.9%), or paclitaxel (0%) showed a significantly higher risk in patients receiving docetaxel than following administration of the other three agents. Conclusions: In breast cancer treatment, compared to other frequently-used agents, monotherapy with docetaxel (100 mg/m(2)) renders a substantial risk of FN (20.9%), thereby justifying the use of primary G-CSF according to international guidelines.
