CSF3 and metastatic malignant neoplasm: In this retrospective analysis of patients receiving myelosuppressive chemotherapy for metastatic cancer at four US health systems, use of G-CSF prophylaxis varied considerably based on chemotherapy regimen FN risk and presence of patient risk factors for FN, ranging from 13.8% to 48.5% in cycle 1 and 26.2% to 57.5% during the course for IR + 1 and HR patients, respectively.