Cytokine supportive care with the colony-stimulating factors G-CSF (granulocyte colony–stimulating factor) or GM-CSF (granulocyte-macrophage colony–stimulating factor) is used widely for patients who are undergoing chemotherapy or stem-cell transplantation. Shorter duration of neutropenia and lower infection rates have been reported with CSF use, but the effect of CSFs on rates of serious infection and overall mortality has been unclear because of the small size of individual studies. Researchers evaluated all-cause and infection-related mortality rates in a comprehensive meta-analysis of randomized controlled trials in which G-CSF or GM-CSF was compared with placebo or no CSF treatment in chemotherapy or stem-cell–transplantation patients. Studies were …