Colony-Stimulating Factor Use and Impact on Febrile Neutropenia Among Patients with Newly Diagnosed Breast, Colorectal, or Non-Small Cell Lung Cancer Who Were Receiving Chemotherapy

Study Objective. To determine the impact of primary prophylactic colony-stimulating factor (CSF) use on febrile neutropenia in a large patient population receiving contemporary chemotherapy regimens to treat breast cancer, colorectal cancer, or non-small cell lung cancer (NSCLC). Design. Retrospective claims analysis. Data Sources. The Surveillance, Epidemiology, and End Results (SEER)-Puget Sound cancer registry and insurance claims records. Patients. A total of 2728 patients aged 25 years or older who received a diagnosis of breast cancer (998 patients), colorectal cancer (688 patients), or NSCLC (1042 patients) between January 1, 2002, and December 31, 2005, and received chemotherapy. Measurements and Main Results. Initial chemotherapy regimen, CSF use (filgrastim or pegfilgrastim), and febrile neutropenia events were evaluated after the first chemotherapy administration. Subsequently, febrile neutropenia rates in patients receiving primary prophylactic CSF were compared with febrile neutropenia rates in patients receiving CSF in settings other than primary prophylaxis or not at all. The impact of primary prophylactic CSF could not be assessed for patients with colorectal cancer or NSCLC because only 1 and 18 febrile neutropenia events, respectively, occurred in those receiving primary prophylactic CSF. Of the 998 patients with breast cancer, 72 (7.2%) experienced febrile neutropenia, 28 of whom received primary prophylactic CSF. In the patients with breast cancer, we observed that primary prophylactic CSF use was associated with reduced febrile neutropenia rates; however, the analysis may have been confounded by unmeasured factors associated with febrile neutropenia. Conclusion. The impact of primary prophylactic CSFs on febrile neutropenia rates could not be demonstrated. Given the substantive cost of CSFs to pharmacy budgets, there are numerous opportunities for pharmacists to optimize CSF use. Research studies are needed to evaluate if guideline-directed prescribing of primary prophylactic CSFs can improve clinical outcomes.