Effect of Primary Prophylactic Granulocyte-Colony Stimulating Factor Use on Incidence of Neutropenia Hospitalizations for Elderly Early-stage Breast Cancer Patients Receiving Chemotherapy

Objective: Chemotherapy is vital for breast cancer management, but early-onset toxicities like neutropenia hinder its administration, especially in the elderly. Primary prophylactic (PP) use of granulocyte-colony stimulating factors (G-CSF) helps prevent neutropenia and its complications while receiving chemotherapy. Nevertheless, evidence supporting the effectiveness of PPG-CSF in the elderly is limited. Thus, the American Society of Clinical Oncology (ASCO) guidelines for PPG-CSF use in the elderly are not explicit. This study analyzed the effects of administration of PPG-CSF and duration of administration on the occurrence of chemotherapy-induced neutropenia hospitalizations in elderly breast cancer patients. Methods: This retrospective observational study of newly diagnosed breast cancer patients receiving chemotherapy used Surveillance, Epidemiology, and End Results-Medicare data from 1994 to 2003. To account for the nonrandom nature of the observational data, a nonparametric matching technique was used to preprocess the data before parametrically estimating the treatment effects. Results: Administration of PPG-CSF during the first course chemotherapy reduced neutropenia hospitalizations by 16% within the first 3 months and 17% within the first 6 months of chemo therapy initiation (P < 0.05). Hospitalization rates within the first 3 months of chemotherapy initiation were 3 times higher in women receiving less than 5 consecutive days of PPG-CSF compared with women receiving PPG-CSF for 5 or more days (P < 0.05). Hospitalization rates within the first 1 and 6 months were also lower with longer PPG-CSF duration (>= 5 d) (P < 0.10). Conclusions: PPG-CSF use is associated with reductions in in-patient healthcare utilization. These findings have implications for ASCO guidelines and Medicare coverage policies for PPG-CSF administration in elderly breast cancer patients.