Incidence and Predictors of Febrile Neutropenia among Early-Stage Breast Cancer Patients Receiving Anthracycline-Based Chemotherapy in Korea

<b><i>Objective:</i></b> This retrospective study was undertaken to assess the incidence of and risk factors for febrile neutropenia (FN) during adjuvant chemotherapy for early-stage breast cancer (ESBC). <b><i>Methods:</i></b> A multicenter survey of three tertiary hospitals was conducted, with data extracted from the records of ESBC patients treated with adjuvant chemotherapy containing AC (doxorubicin, 60 mg/m² and cyclophosphamide, 600 mg/m² every 21 days). Assessments included clinical characteristics, chemotherapy dose modifications, and incidence of FN. <b><i>Results:</i></b> A total of 610 patients were included for analysis. The incidence of grade 4 neutropenia and FN was 44.6 and 8.5%, respectively. Reduced relative dose intensity (RDI) less than 85% occurred in 11.0% of patients, and there were treatment delays in 12.6% of patients. Multivariate analysis identified several independent predictors for FN, including the presence of grade 4 neutropenia and pretreatment calculated estimated glomerular filtration rate less than 60 ml/min. <b><i>Conclusion:</i></b> Patients with ESBC are at substantial risk for FN and reduced RDI when treated with adjuvant AC chemotherapy. Predictive models based on risk factors identified in this study should enable the selective application of supportive measures in an effort to deliver the full dose of chemotherapy.