Incidence of febrile neutropenia with docetaxel plus cyclophosphamide in a university-based breast oncology clinic.

Abstract

9061 Background: ASCO guidelines indicate that an incidence of febrile neutropenia (FN) greater than 20 percent justifies the use of prophylactic granulocyte colony stimulating factor (G-CSF) after a particular chemotherapy regimen. Docetaxel plus cyclophosphamide (TC) is a commonly used chemotherapeutic regimen for patients with early stage breast cancer, and an FN incidence of 5 percent has been reported by Jones, et al with this regimen. In clinical practice, the incidence of FN with TC may be higher than previously reported, and we sought to determine the incidence of febrile neutropenia in our outpatient clinic. Methods: We conducted a retrospective review of paper and electronic records for 130 patients with early-stage breast cancer who received at least one standard dose cycle of docetaxel (75 mg/m2) and cyclophosphamide (600 mg/m2) at a university-based practice between November 2007 and August 2010. Fever was defined as a temperature > 101 degrees Fahrenheit or clinician-defined fever, and neutropenia was defined as an absolute neutrophil count < 500 (grade 4 neutropenia). Chi-squared analysis was used for categorical data. Results: One hundred of 130 patients studied did not receive primary prophylactic G-CSF. The incidence of febrile neutropenia was found to be 23 percent amongst these 100 patients who received at least one cycle of TC without prophylactic G-CSF versus 3 percent of the 30 patients who received G-CSF starting cycle one (p = 0.015). Seventy-six of the 100 patients not receiving cycle one G-CSF experienced grade 4 neutropenia. The average length of hospitalization for those with FN was 3.14 days. Incidence of FN was not significantly affected by age, and this data is summarized in the table below (p = 0.658). Conclusions: The incidence of FN in the current study is higher than expected based on initial reports with the TC regimen. This warrants investigation in larger cohorts to determine whether primary prophylactic G-CSF should be considered to limit this morbidity for patients receiving TC. FN [n (%)] No FN [n (%)] Total Age ≤ 50 6 (18%) 28 (82%) 34 Age 51-64 14 (26%) 40 (74%) 54 Age ≥ 65 3 (25%) 9 (75%) 12 Total 23 (23%) 77 (77%) 100