The use of granulocyte colony-stimulating factors (G-CSF) significantly reduces febrile neutropenia (FN) risk and has helped maintain dose intensity and dose density when treating breast cancer with chemotherapy. This is crucial as survival outcomes are significantly impaired if dose intensity are reduced. National and international guidelines recommend the use of G-CSF as primary prophylaxis with most commonly used breast cancer chemotherapy regimens. Filgrastim (FIL) as a G-CSF that has been in use since the early 90s. Pegfilgrastim (PEG) is a long-acting, pegylated version of FIL that requires only one injection per chemotherapy cycle instead of daily FIL injections for 5 to 10 days per cycle. PEG and FIL both come at the potential cost of bone pain, the most common side effect. G-CSF related bone pain is often severe, leading to refusal or cancellation of G-CSF and early discontinuation of chemotherapy. We propose to perform a pragmatic, multicenter, open-label, randomized clinical trial to compare bone pain experienced by patients receiving either PEG or 5-day-FIL with neoadjuvant or adjuvant chemotherapy.
