The Dosing and Outcomes Study of Erythropoietic Stimulating Therapies (DOSE) is a prospective, observational multicenter registry of approximately 1200 adult cancer patients receiving treatment with EST; eg, epoetin alfa or darbepoetin alfa. The planned duration of the DOSE Registry is three years. Based on initial results, the registry sponsor may elect to extend the duration of the registry.This study does not specify treatment protocols, require any particular assignment of patients to treatment protocols, or in any other way require participating physicians to alter their practice patterns. Participating physicians are instructed to continue to treat all patients according to their own best clinical judgment, but to submit information on baseline patient characteristics, treatment patterns, and clinical outcomes. Baseline determinations will include patient demographics, tumor and treatment type, hematologic parameters, and patient reported outcomes. Data will be collected over the 16-week study period with regard to EST treatment, hematologic outcomes and patient reported outcomes.