Impaired cognition, fatigue, and diminished quality of life (QOL) are commonly associated with breast cancer chemotherapy. This randomized, double-blind, placebo-controlled pilot trial assessed the feasibility of quantifying the effects of epoetin alfa on cognitive function and mood, and evaluated its effects on fatigue and QOL in patients with breast cancer treated with anthracycline-based adjuvant or neoadjuvant chemotherapy. Patients were randomized to receive epoetin alfa 40,000 U subcutaneously once weekly or placebo at the beginning of 4 cycles of chemotherapy administered over 12 weeks. Cognitive function was assessed by Executive Interview (EXIT25) and Clock Drawing Tasks; mood by Profile of Mood States; anemia-related symptoms, including fatigue, by the Functional Assessment of Cancer Therapy-Anemia (FACT-An) subscale; and QOL by Linear Analog Scale Assessment. Ninety-four patients were evaluable for efficacy and safety. Mean change in EXIT25 scores from baseline to cycle 4 in the epoetin alfa group was 1.3 +/- 3.3; the mean change was 0.3 +/- 2.4 in the placebo group (a negative change indicates improved executive function). There was no difference between groups in mean change in EXIT25 score from baseline to 6-month follow-up assessment. Mean hemoglobin levels were higher in the epoetin alfa group compared with the placebo group after 4 cycles of chemotherapy. Epoetin alfa recipients had less of a decrease in FACT-An subscale scores from baseline to cycle 4 and improvement in FACT-An subscale scores at 6-month follow-up assessment compared with placebo. Epoetin alfa therapy was well tolerated. These data suggest that epoetin alfa may have attenuated the cognitive impairment and fatigue that occurred during adjuvant breast cancer chemotherapy.