Temporal and Geographic Variation in the Use of Hematopoietic Growth Factors in Older Women Receiving Breast Cancer Chemotherapy: Findings From a Large Population-Based Cohort

Purpose Hematopoietic growth factors have played a major role in preventing infection and shortening the duration of neutropenia in patients receiving cancer chemotherapy. Little information is available on how these growth factors are used in patients with cancer outside the clinical trial setting. We performed descriptive and exploratory analyses on the patterns and correlates of the use of hematopoietic growth factors in community-dwelling elderly patients. Patients and Methods We identified 5,843 women from the Surveillance, Epidemiology, and End Results (SEER)–Medicare-linked data cohorts who were diagnosed with breast cancer at age 65 or older in 1992 to 1999 from the 11 SEER areas and received chemotherapy. Results Overall, 17.3% of the elderly women with breast cancer chemotherapy received filgrastim and 6.8% received epoetin. The use of the growth factors increased significantly over time from 1992 to 1999 (P < .001 for trend). Compared with patients diagnosed in 1992 to 1994, patients diagnosed in 1998 to 1999 were more than five times and 65 times more likely to receive filgrastim and epoetin, respectively, after controlling for other factors such as age and comorbidity. There also was substantial geographic variation in the use of hematopoietic growth factors, ranging from 10.6% in Seattle to 22.9% in Atlanta. Significant predictors of growth factors included patient age, race, tumor stage, and comorbidity. Conclusion There were substantial temporal and geographic variations in the use of hematopoietic growth factors among patients receiving chemotherapy for breast cancer. The nationwide and population-based Medicare claims provide potential for examining the effectiveness, medical costs, and cost effectiveness of hematopoietic growth factors in the community.