Risk assessment and guidelines for first-cycle colony-stimulating factor use in the management of chemotherapy-induced neutropenia.

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.