Neutropenia and G-CSF use in patients receiving FOLFOX during the COVID-19 pandemic

BackgroundDuring the COVID-19 pandemic, guidance broadened indications for primary G-CSF prophylaxis to reduce chemotherapy-related neutropenia while minimizing clinic visits. Evidence on the optimal duration of daily G-CSF in biweekly FOLFOX remains limited, particularly in gastrointestinal malignancies.MethodsWe conducted a retrospective study of COVID-negative adults with gastrointestinal cancers receiving FOLFOX during the pandemic. Patients were categorized by G-CSF strategy: no prophylaxis, 3-day filgrastim, or 5-day filgrastim. Primary outcomes were overall neutropenia and grade 3-4 neutropenia. Secondary outcomes included treatment modifications and adverse events. Multivariable logistic regression assessed independent associations.ResultsNeutropenia was higher without G-CSF versus 3-day and 5-day (64.4% vs 37.1% vs 39.6; p < 0.001); grade 3-4 neutropenia likewise (30.1% vs 7.9% vs 11.9; p < 0.001). 3-day vs 5-day showed no significant difference (neutropenia p = 0.67; grade 3-4 p = 0.29). G-CSF use independently lowered neutropenia risk; female sex independently increased risk.ConclusionIn patients receiving biweekly FOLFOX for gastrointestinal cancers, primary G-CSF prophylaxis was associated with lower rates of neutropenia. No statistically significant difference was observed between the 3-day and 5-day daily G-CSF schedules in this cohort. However, given the retrospective design and the absence of a predefined non-inferiority framework, these findings do not establish equivalence and should be interpreted with caution. Prospective multicenter studies specifically designed to compare 3- and 5-day regimens are warranted.