Patterns of primary prophylactic granulocyte colony-stimulating factor use in older Medicare patients with cancer receiving myelosuppressive chemotherapy.

PURPOSE: Guidelines recommend primary prophylactic (PP) granulocyte colony stimulating factor (G-CSF) for prevention of febrile neutropenia (FN) in patients receiving myelosuppressive chemotherapy with high risk (HR: > 20%), or intermediate risk (IR:10-20%) of FN and ≥ 1 patient risk factor (e.g., age ≥ 65y). The current retrospective cohort study describes patterns of PP-G-CSF in older Medicare patients undergoing myelosuppressive chemotherapy with HR/IR of FN. METHODS: Patients aged ≥ 66y initiating chemotherapy regimens with HR/IR of FN to treat breast, colorectal, lung, or ovarian cancer, or Non-Hodgkin's Lymphoma were selected using Medicare 20% sample (2013-2015) and 100% cancer patient (2014-2017) data. PP-G-CSF use was identified in the first cycle. Timing of pegfilgrastim pre-filled syringe (PFS) administration, proportion of patients completing all cycles (adherence) with pegfilgrastim PFS or on-body injector (OBI), and duration of short-acting G-CSF (sG-CSF) was described across all cycles. RESULTS: Of 64,893 patients receiving HR/IR for FN, 71% received HR and 29% IR regimens. Overall, PP-G-CSF use in the first cycle was 53% (HR: 74%; IR: 44%) and varied across cancers. Adherence with pegfilgrastim was slightly higher among OBI initiators (78%) than PFS (74%). Number of PP-sG-CSF administrations (mean [SD]) per cycle was 5.1 (SD: 2.7) overall, 5.4 (2.6) for HR, and 4.9 (2.7) for IR. CONCLUSION: Despite cancer treatment guidelines recommending PP-G-CSF use to reduce risk of FN associated with HR and IR (with ≥ 1 patient risk-factor) regimens, PP-G-CSF remains underutilized in older patients, across cancer types and regimens. Opportunities exist for improvement in use of PP-G-CSF.