Abstract P6-07-07: Febrile neutropenia primary prophylaxis with granulocyte-colony stimulating factors (G-CSF) in breast cancer

Abstract

Abstract Background: Febrile neutropenia (FN) during adjuvant chemotherapy is associated with significant morbidity, mortality risk and incremental costs. It could also lead to chemotherapy dose reductions and worse cancer outcomes. Patients who develop FN are often prescribed secondary G-CSF prophylaxis with subsequent chemotherapy cycles to decrease the risk of further episodes of infection. Practice guidelines also recommend primary G-CSF prophylaxis for: i) patients treated with chemotherapeutic regimens associated with FN risks > 20% and ii) patients treated with regimens associated with 10-20% FN risk in the presence of other patient-related factors that further increase the risk of FN. The adoption of primary G-CSF prophylaxis in clinical practice however depend on the “value for money” associated with G-CSF prophylaxis at various FN risks, where incremental cost-utility values below $100,000 per quality adjusted life year (QALY) gains are generally considered to be cost-effective. Aim: To examine the “value for money” associated with primary and secondary G-CSF prophylaxis strategies, compared with a no G-CSF strategy, for adjuvant chemotherapy in breast cancer at varying FN risks. Methods: The incremental costs and QALYs associated with G-CSF prophylaxis (primary or secondary) were examined through a decision analysis framework that incorporated i) upfront costs of G-CSF treatment (primary or secondary); ii) varying rates of baseline FN risks and iii) downstream costs and QALY gains associated with adjuvant chemotherapy based on chemotherapy dose levels (0, -1, and -2) and G-CSF prophylaxis. The primary analysis involved adjuvant TC (taxotere & cyclophosphamide) chemotherapy regimen delivered every three weeks for four cycles. Probabilities and utilities were derived from the literature, and treatment costs were based on local resources. The robustness of the model to plausible ranges of uncertainty around key parameters / assumptions was examined in sensitivity analyses. Results: Primary G-CSF prophylaxis was a cost-effective strategy compared with secondary G-CSF prophylaxis in the base case scenario. The “value for money” associated with primary G-CSF prophylaxis however was dependant on the baseline FN risk without G-CSF, and assumptions around the impact of chemotherapy dose reductions on breast cancer relapse and mortality. Two way sensitivity analyses illustrated plausible combinations of baseline FN risks and detrimental impact of reduced chemotherapy dose associated with favorable value for money. Conclusions: Primary G-CSF prophylaxis overall appears to be a cost-effective strategy for patients at high FN risk. The FN threshold at which primary G-CSF is associated with good value for money is however dependent on the potential detrimental impact of reduced chemotherapy dose on breast cancer outcomes. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-07-07.