Hematopoietic management in oncology practice. Part 1. Myeloid growth factors.

Hematopoietic growth factors have transformed the practice of oncology. The two major factors in clinical use are recombinant human (rh) granulocyte colony-stimulating factor (G-CSF, filgrastin [Neupogen]) and granulocyte-macrophage colony-stimulating factor (GM-CSF, sargramostim [Leukine]). These factors differ significantly in their role in hematopoiesis and the regulation of mature effector cell function. G-CSF regulates both basal and neutrophil production and increased production and release of neutrophils from the marrow in response to infection. GM-CSF mediates its effects on the neutrophil lineage through its effects on phagocytic accessory cells and its synergy with G-CSF, but it does not appear to have a role in basal hematopoiesis. Part 1 of this two-part series focuses on the use of the myeloid growth factors rhG-CSF and rhGM-CSF to shorten the duration of chemotherapy-induced neutropenia and thus prevent infection in cancer patients. In randomized trials, rhG-CSF has consistently decreased the duration of neutropenia during all cycles of chemotherapy and reduced the risk of infection by 50% or more. Trials of rhGM-CSF have not reported consistent results.