Use of colony stimulating factors (CSF) for primary prophylaxis of chemotherapy-induced neutropenia in community oncology practices to reduce risk of febrile neutropenia (FN)

Abstract

17013 Background: In addition to proof of efficacy from randomized controlled trials (RCTs), health care decision makers need data on therapy effectiveness, specifically how well an intervention performs in routine practice. While the efficacy of filgrastim and pegfilgrastim in preventing FN has been established in RCTs, their effectiveness in community practice has not been studied. Methods: Data were obtained from medical records of patients treated with chemotherapy for a variety of malignancies in a random sample of 99 US community oncology practices in 2001 and 2003 (before and after FDA approval of pegfilgrastim in 2002). Patients receiving filgrastim or pegfilgrastim and, in 2003, every third patient not treated with a CSF, were consecutively sampled(n=6148). Only those receiving chemotherapy on 3–4 wk cycles were included in this analysis (n=3,744). Primary prophylaxis was defined as receipt of CSF within 3 days of the 1st cycle of chemotherapy. Multivariable logistic regression, adjusted for patient and treatment characteristics and weighted for patient sampling was used to estimate the odds of FN in patients who received primary prophylaxis versus those who were managed expectantly, i.e. patients who received CSF later during chemotherapy or not at all. Results: Of 3744 patients in the study population, 2966 (79%) received a CSF some time during their chemotherapy treatment. In 2003, approximately 18% of patients received CSF primary prophylaxis. Among patients who did not receive primary prophylaxis but received a CSF later during the treatment, 38% initiated CSF in the 1st cycle after day 3. In a multivariate model, increased risk of FN was associated with receiving myelosuppressive chemotherapy (OR 2.19; 95% CI 1.05–4.56) and having 3 or more drugs (vs. 1) in the regimen (OR 2.13; 95% CI 1.09–4.17). Adjusting for patient and treatment characteristics, the relative odds of FN in patients who received CSF primary prophylaxis was 0.70 (95% CI 0.50–0.98) compared with patients who either received CSF later or not at all. Conclusions: In this community practice setting, patients who received CSF primary prophylaxis had significantly lower odds of developing FN than patients managed expectantly. No significant financial relationships to disclose.