Issues on the Use of White Blood Cell Growth Factors in Oncology Practice

Appropriate use of myeloid growth factors may reduce the risk of neutropenic complications including febrile neutropenia (FN) in patients receiving cancer chemotherapy. The recently updated American Society of Clinical Oncology (ASCO) Guidelines on the Use of the White Blood Cell Growth Factors recommends routine prophylaxis with these agents starting in the first cycle when the risk of FN is 20% or greater. However, the risks for neutropenic complications and the risk of serious adverse consequences from FN vary considerably with different chemotherapy regimens as well as other disease-, treatment-, and patient-specific risk factors. Considerably more information is now available on the major risk factors for FN. Multivariable risk models combining factors look promising but require further validation. Most clinical studies of myeloid growth factor prophylaxis assessed relative risk (RR) of FN but were not powered to evaluate the effect of prophylaxis on disease-free or overall survival. Accumulating evidence suggests, however, that the appropriate use of these agents in selected patients may improve both short-term and long-term survival by reducing the immediate risk of mortality accompanying patients with high-risk disease developing FN as well as improving disease-free and overall survival by enabling the delivery of full dose intensity chemotherapy and reducing the risk of disease recurrence in patients treated with curative intent. Further studies to evaluate risk factors and models for FN are needed to guide clinical and shared decision making for the optimal personalized use of these agents and offer patients at increased risk the best chance of long-term disease control.