Abstract P3-15-09: Impact of granulocyte colony-stimulating factors on febrile neutropenia risk during early-stage breast cancer treatment

Febrile neutropenia(FN) is a significant cause of both mortality and morbidity in patients undergoing adjuvant or neoadjuvant chemotherapy for early-stage breast cancer (ESBC). The risk of FN varies with respect to the type of chemotherapy used and patient-specific characteristics. Granulocyte colony-stimulating factors (G-CSF) are recommended, but not mandatory, as primary prophylaxis for patients at high-risk of FN. This study aimed to evaluate the impact of filgrastimand pegfilgastrim on the incidence of FN during adjuvant and neoadjuvant chemotherapy for ESBC. Risk factors for FN were also assessed. We conducted a retrospective cohort study that included 297 consecutive patients undergoing adjuvant or neoadjuvant chemotherapy for ESBC between May 2010 and May 2012. Patients on clinical trials were excluded. 173 patients (58%) received primary G-CSF prophylaxis whereas 124 (42%) did not. In patients receiving G-CSF prophylaxis, filgrastimwas more commonly prescribed (59.9%), due to reimbursement reasons in Quebec. In total, 38 patients (12.8%) manifested at least one episode of FN. The incidence of FN was significantly reduced in patients receiving primary prophylaxis with G-CSF (p = 0.012). The most commonly prescribed chemotherapy protocols were FEC-D (5-Fluorouracil, epirubicin, cyclophosphamide followed by docetaxel), AC-T (Adriamycin, cyclophosphamide followed by paclitaxel), and TC ( docetaxeland cyclophosphamide). The use of G-CSF as primary prophylaxis was associated with a decrease in FN incidence in patients receiving FEC-D and TC. One death occurred in a patient receiving FEC-D who had not received prophylaxis. There was no significant difference in the dosing of filgrastimbetween patients with FN (mean dose received = 5.289 mcg/kg) and those without FN (mean = 5.167mcg/kg) (p = 0.742). Furthermore, previously described risk factors for FN such as age, comorbidities and decreased baseline albumin were not associated with an increased of FN in our study. Although this was a retrospective study with inherent limitations, our cohort included, to our knowledge, the largest number of patients in a study of G-CSF use in ESBC. We found a statistically significant reduction of FN in patients receiving primary G-CSF prophylaxis. Primary prophylaxis should be routinely offered to patients undergoing chemotherapy for ESBC and in particular, to those receiving docetaxel-containing regimens. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-15-09.