Impact of Granulocyte Colony-Stimulating Factor (G-CSF) on Clinical Outcomes in Allogeneic Hematopoietic Cell Transplantation: Does Speeding Up Neutrophil Engraftment Make a Difference?

Background. Despite decades of post–allogeneic hematopoietic cell transplantation (HCT) growth factor utilization, its role remains undefined, leading to ongoing debates and research. The theoretical impacts of growth factors have been challenged in numerous studies. Methods. In this retrospective cohort study conducted at the Princess Margaret Cancer Centre, we analyzed the clinical outcomes of 509 patients who underwent allogeneic HCT between May 1, 2019, and May 31, 2022. This study aimed to assess the impact of granulocyte colony-stimulating factor (G-CSF) administration posttransplantation on neutrophil and platelet engraftment, incidence of bloodstream infections (BSIs), graft-versus-host disease, engraftment syndrome (ES), and survival metrics including overall survival, nonrelapse mortality, and graft-versus-host disease–free/relapse-free survival. Results. Our findings indicate that G-CSF administration expedited neutrophil engraftment (16 versus 18 d, P = 0.009) and was associated with a decreased incidence of BSI (9.4% versus 31.3%, P = 0.014). However, this benefit was counterbalanced by a significant delay in platelet engraftment (21 versus 17 d, P