Comparing risk models guiding growth factor use in chemotherapy

Chemotherapy-induced neutropenia (CIN) and its corollary febrile neutropenia (FN) are well recognized, and they are serious consequences of many agents used in the treatment of malignancy. FN in particular has been associated with a considerable risk of morbidity and mortality, namely sepsis with multiorgan failure and eventual death.1 The mainstay of prophylaxis for patients who are deemed to be at high risk for CIN and FN is colony-stimulating factors (CSF). These agents have been shown to significantly decrease FN-related mortality, and therefore their use is potentially lifesaving.2 However, CSF are not cheap, with the cost of peg-filgrastim as much as US $6195.99 per cycle of chemotherapy.3 Therefore, not only do FN and CIN pose significant risk to patients, they also carry a high burden of cost to the patient and health care system both in treatment and prophylaxis.4 As such, it is prudent for oncologists to accurately identify high-risk patients and judiciously use CSF in an evidence-based manner. However, this has proven to be difficult because of the extent of variability between patients and the heterogeneity of the various risk models in the literature. Currently, there are 2 widely used guidelines, 1 developed by the National Comprehensive Cancer Network (NCCN) and another by the American Society of Clinical Oncology (ASCO). Both guidelines suggest the use of prophylactic CSF if the chemotherapy regimen has an FN risk of more than 20% (high risk). If the chemotherapy is deemed to be of intermediate risk (10%-20% FN risk), then patient-specific factors need to be considered.5,6 In lung cancer, the NCCN lists only topotecan for small cell carcinomas as being high risk for FN, and therefore it is the only regimen that would warrant definitive use of prophylactic CSF.5 The most recent ASCO guidelines do not list chemotherapy regimens that are high risk for FN.6 For intermediate-risk regimens, the NCCN states that CSF prophylaxis should be considered if the patient has had previous chemotherapy or radiation therapy, persistent neutropenia, bone marrow involvement by