Patterns of Granulocyte Colony-Stimulating Factor (G-CSF) Use in Elderly Patients with Non-Hodgkin's Lymphoma (NHL) Receiving Myelosuppressive Chemotherapy

Febrile neutropenia (FN) is a common and potentially serious complication of myelosuppressive chemotherapy in cancer patients. Oncology guidelines recommend primary G-CSF prophylaxis (PPG) in patients with a high risk of developing FN, which is risk > 20% based on myelotoxicity of the regimen itself or from a combination of the therapy, older age, comorbidities and disease characteristics (Lyman Cancer 2011, Crawford J Natl Compr Canc Netw 2011, Aapro Support Care Cancer 2010). There is a gap in the medical literature concerning current patterns of G-CSF use and FN occurrence among the elderly Medicare population receiving myelosuppressive chemotherapy for NHL. To correct this, we performed a retrospective analysis using a subset of the Medicare 5% database.

The Medicare 5% claims data set (includes a representative 5% systematic sample of Medicare beneficiaries) was used to identify NHL patients age 65+ initiating chemotherapy between July 1, 2003 and June 30, 2009. Chemotherapy courses were identified for each patient; only the first course was used for this analysis. Using the National Comprehensive Cancer Network guidelines on Myeloid Growth Factors (NCCN V1. 2012), if they could be, chemotherapy course regimens were classified as high risk (HR, FN risk ≥ 20%) or intermediate risk (IR, FN risk ≥ 10% and < 20%) for FN. Up to 9 chemotherapy cycles were defined for the first course. Cycle one began on the first chemotherapy claim date and ended at the next chemotherapy claim occurring at least 20 days after the chemotherapy initiation; subsequent cycles were similarly defined. First administration of G-CSF [filgrastim (NEUPOGEN®) or pegfilgrastim (Neulasta®)] was classified as either PPG (within first 5 days of the beginning of the first cycle), secondary prophylaxis (within first 5 days of second or subsequent cycles), or reactive (day 6 or later of first or subsequent cycles). FN assessed during the chemotherapy course was defined as hospitalization with a code for neutropenia in any claim position.

We identified 1, 104 chemotherapy courses with high FN risk, the vast majority of which (1, 027) were R-CHOP. We also identified 77 courses with intermediate FN risk. Approximately sixty four percent of HR regimens and 77% of IR regimens were initiated without primary prophylaxis with growth factor. Daily filgrastim was used in 10% of PPG, and pegfilgrastim in 90%. Among HR courses, 22. 6% had ≥ 1 FN hospitalization and 5. 4% had ≥ 2; among IR courses 10% had 1 FN hospitalization.

The use of prophylactic growth factor support is the recommended standard of care in elderly patients receiving R-CHOP (Repetto Eur J Cancer 2003). In this study the majority of elderly patients initiating R-CHOP chemotherapy did so without appropriate growth factor support which translated into a high incidence of FN hospitalizations (22. 1%).

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