P5-20-07: Estimation of Febrile Neutropenia in Women Receiving Docetaxel Plus Cyclophosphamide as Adjuvant Therapy for Early Stage Breast Cancer: A Retrospective Analysis.

Abstract

Abstract Background: US Oncology Trial 9735 (Jones S, et al. JCO. 2006;24:5381–5387) established the docetaxel plus cyclophosphamide (TC) regimen as an effective adjuvant therapy for early stage breast cancer (ESBC). This trial did not specifically evaluate the incidence of febrile neutropenia (FN) as a study endpoint, but rates of 4%-8% were reported. Prophylactic granulocyte colony-stimulating factor (G-CSF) support was not allowed; reactive G-CSF support overall was not reported. Subsequent reports in the community setting have indicated FN rates of 25%-50% without G-CSF support and 0%-6.3% with G-CSF support (Table 1). To better determine the incidence of FN among ESBC patients treated with TC, we performed a retrospective clinical data review from the electronic medical record (EMR) database of Georgia Cancer Specialists, a large community oncology practice. Methods: EMR data were captured between January 2006 and March 2010. Eligibility included women ≥ 18 years old with ESBC (stage I-IIIA) who completed ≥ 1 cycle of TC. The study time period was from the first dose of chemotherapy (CTX) to 6 weeks after the last dose of CTX, death, or loss to follow-up. The primary endpoint was the incidence of FN. Other endpoints included the incidence of severe (grade 3/4) neutropenia, neutropenia-related hospitalizations, G-CSF use, relative dose intensity (RDI), and dose delays and reductions. Results: Data from 662 patients were included in the analysis. Median age was 55 (range: 25–81) years. 40% of patients were white. The median number of CTX cycles received was 4 (range: 1–6). Most patients (91%) received G-CSF support; 73% as primary prophylaxis. See Table 2 for additional results. Conclusions: This is the largest retrospective, community-based study to evaluate the incidence of FN in ESBC patients treated with TC. The observed FN rate of 5% (with 91% of patients receiving G-CSF) is consistent with other published reports using TC (Table 1). Our results suggest that TC is a taxane regimen with clinically significant myelosuppression (similar to other commonly used regimens in ESBC, such as TAC [NCCN Guidelines v2.2011]) and that the use of G-CSF support should always be considered. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-20-07.