Can hematopoietic growth factors be used to improve the success of cytotoxic chemotherapy?

Hematopoietic growth factors (HGFs) have provided oncologists with powerful tools to investigate questions of chemotherapy dose and treatment outcome in cancer patients. Agents such as recombinant granulocyte colony-stimulating factor (e.g. G-CSF; filgrastim) significantly accelerate neutrophil recovery after chemotherapy and therefore allow the delivery of a planned dose on time. Moreover, it is possible to investigate the effects of escalated dose chemotherapy with HGF support. This can be done using the HGF alone or in conjunction with stem cell rescue. HGFs significantly reduce morbidity following bone marrow transplantation (BMT) and may also be used to mobilize peripheral blood progenitor cells (PBPC) to support high-dose chemotherapy. Growth factor-mobilized PBPC have practical and clinical advantages over BMT and may be a more effective method of allowing the delivery of high-dose therapy, but for some patients (who for reasons not yet clear, display a poor mobilization response) a combination of autologous bone marrow and PBPC might be more effective at reconstituting hematopoiesis. Whether more intensive treatment approaches will significantly improve survival remains to be determined.