Monica N. Fornier, MD

Breast cancer is the most common noncutaneous malignancy inwomen in industrialized countries. Chemotherapy prolongs survival inpatients with early-stage breast cancer, and maintaining the chemotherapydose intensity is crucial for increasing overall survival. Manypatients are, however, treated with less than the standard dose intensitybecause of neutropenia and its complications. Prophylactic colonystimulatingfactor (CSF) reduces the incidence and duration of neutropenia,facilitating the delivery of the planned chemotherapy doses.Targeting CSF to only at-risk patients is cost-effective, and predictivemodels are being investigated and developed to make it possible forclinicians to identify patients who are at highest risk for neutropeniccomplications. Both conditional risk factors (eg, the depth of the firstcycleabsolute neutrophil count nadir) and unconditional risk factors(eg, patient age, treatment regimen, and pretreatment blood cell counts)are predictors of neutropenic complications in early-stage breast cancer.Colony-stimulating factor targeted toward high-risk patients startingin the first cycle of chemotherapy may make it possible for fulldoses of chemotherapy to be administered, thereby maximizing patientbenefit. Recent studies of dose-dense chemotherapy regimens with CSFsupport in early-stage breast cancer have shown improvements in disease-free and overall survival, with less hematologic toxicity than withconventional therapy. These findings could lead to changes in how earlystagebreast cancer is managed.