ONCOLOGY Vol 20 No 5_Suppl_4

Chemotherapy-induced neutropenia (CIN) and its complications exact a substantial toll on patients with cancer. Febrile neutropenia (FN), a sign of life-threatening infections, is associated with lengthy hospitalizations, early mortality, and high medical costs. In addition, neutropenia is the primary cause of dose reductions and dose delays, limiting the delivery of the chemotherapy at full dose and on schedule and thus compromising long-term survival in patients with potentially curable malignancies. Many recent studies in several major tumor types have documented that the greatest risk of neutropenia and its complications is in the first cycle of chemotherapy, with more than 50% of the first episodes of neutropenia and FN occurring in the first cycle. In addition to their other negative effects, these first-cycle events are also associated with early termination of the chemotherapy. The disproportionately high risk of neutropenia in the first cycle has important implications for managing CIN, as well as for the development and use of guidelines for supportive care. It highlights the importance of determining which patients are at high risk for neutropenia and its complications before the chemotherapy is initiated and implementing interventions, such as prophylactic growth factor support in the first and subsequent cycles, to reduce that risk.

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 ≥ 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.

Chemotherapy-induced neutropenia (CIN) is the primary dose-limiting toxicity in patients being treated for cancer. The substantial toll of CIN includes febrile neutropenia (FN), hospitalization, infection, early mortality, increased medical costs, decreased quality of life, and the potential for diminished long-term survival due to chemotherapy dose reductions and delays.