The use of granulocyte colony stimulating factor (G-CSF) during polychemotherapy regimens has been increasing. International guidelines recommend primary prophylaxis when the risk of neutropenic complications exceeds 20% and as a result, G-CSF is often used outside of PBS reimbursement via various funding models. The aim of this audit was to evaluate the use of G-CSF over the past decade in a series of early breast cancer patients treated in an Australian tertiary hospital.
We retrospectively identified patients receiving (neo)adjuvant chemotherapy for early breast cancer in two cohorts: “early” 2005-10 and “late” 2011-16 at Austin Health. Chemotherapy regimens, G-CSF use and schedule were compared along with rates of febrile neutropenia (FN) for the 2011-16 cohort.
Between 2005-2016, 655 patients received the following curative chemotherapy regimens: 103 (16%) anthracycline-based (FEC), 171 (26%) taxane-based (TC = 147; TcarboH = 34) and 371 (57%) combined regimens (FEC-D = 169; AC-T (+/-H) = 191); TAC = 11). A similar proportion of patients received PBS-qualifying primary prophylaxis (10% versus 9% respectively). There was a substantial increase in G-CSF use over time with 61% (all using pegfilgrastim) in the early compared with 90% (52% pegfilgrastim and 48% filgrastim) in the late cohort. Thirty patients who initially received filgrastim were subsequently changed to pegfilgrastim at a later cycle. Fifty-four (19%) early cohort patients received G-CSF from cycle 1 compared with 266 (73%) in the late cohort. Thirty-one (9%) patients had a febrile neutropenic event in the late cohort, 21 (69%) of whom were already receiving G-CSF. The rate of FN was stable year on year from 2011-16.
G-CSF use has increased substantially over the past decade despite no increase in the prescribing of our most myelosuppressive regimens. Increasing availability and fall in cost of short-acting preparations have diversified prescribing.