Efficacy of prophylactic pegfilgrastim compared with therapeutic filgrastim for preventing febrile neutropenia during chemotherapy for musculoskeletal tumors: A single-center retrospective study.

BACKGROUND: Febrile neutropenia (FN) is a serious adverse event of chemotherapy that can lead to treatment delays, dose reductions, and life-threatening infections. Prophylactic pegylated granulocyte colony-stimulating factor (peg G-CSF; pegfilgrastim) is recommended to reduce FN risk; however, evidence in patients with musculoskeletal tumors receiving diverse chemotherapy regimens remains limited. METHODS: We retrospectively reviewed 20 patients (104 chemotherapy administrations) with musculoskeletal tumors treated at a single institution between May 2014 and April 2017. Each patient had received at least one cycle of the same regimen with therapeutic filgrastim prior to switching to prophylactic pegfilgrastim, allowing a within-patient comparison. FN incidence and grade 3/4 neutropenia incidence were compared between the filgrastim group (53 administrations) and the pegfilgrastim group (51 administrations) using Fisher's exact test. RESULTS: FN incidence was significantly lower in the pegfilgrastim group (7.8% vs. 26.4%; odds ratio 0.24, 95% CI 0.07-0.78; P = 0.018), as was grade 3/4 neutropenia (60.8% vs. 100%; P < 0.001). In subgroup analyses by regimen, FN was numerically reduced across all regimens but did not reach statistical significance in any individual subgroup, likely owing to limited statistical power. By diagnosis, FN was significantly reduced in osteosarcoma (P = 0.045) but did not reach significance in other diagnostic subgroups. No significant differences were observed in chemotherapy dose intensity, number of cycles, or length of hospital stay. CONCLUSIONS: Prophylactic pegfilgrastim significantly reduced FN and severe neutropenia compared with therapeutic filgrastim in musculoskeletal tumor chemotherapy, suggesting that it may offer a clinically meaningful benefit in this patient population and warranting further prospective investigation.