Neutropenia is the primary dose-limiting toxicity in patients with
cancer treated with systemic
chemotherapy. The risk of
febrile neutropenia (FN) has been estimated on the basis of the
chemotherapy regimen, but studies are now finding a number of patient-related and disease-related risk factors for FN and other complications, such as hospitalization,
chemotherapy dose reductions and delays, and mortality. These patient-related risk factors have been incorporated into clinical guidelines for managing
neutropenia. The newly released guidelines on the use of myeloid
growth factors with
cancer chemotherapy of the National Comprehensive
Cancer Network use disease- and patient-related factors along with the
chemotherapy regimen risk. These guidelines also differ from previous guidelines in that they recommend the routine use of
colony-stimulating factors (CSFs) in patients in whom the risk of
neutropenia is > 20% (the previous threshold was > or = 40%); this recommendation is based on recent data that show the clinical benefits of
filgrastim (
Neupogen) and
pegfilgrastim (
Neulasta) in studies in which the overall populations had FN risks of between 20% and 40%. The use of guidelines such as these in clinical practice will make it possible to target CSFs to appropriate patients in the first cycle of
chemotherapy, when the risk of
neutropenia is highest.