A randomized, double-blind, placebo-controlled study of oral coenzyme Q to relieve self-reported treatment-related fatigue in newly diagnosed patients with breast cancer

Background: Coenzyme Q (CoQ) is a common antioxidant supplement with known cardioprotective effects and potential anticancer benefits. Objectives We performed a randomized, double-blind, placebo-controlled study of oral CoQ in female breast cancer patients with the primary objective of determining CoQ's effects on self-reported fatigue, depression, and quality of life (QOL). Methods: Eligible women with newly diagnosed breast cancer and planned adjuvant chemotherapy were randomized to oral supplements of 300 mg CoQ or placebo, each combined with 300 IU vitamin E, divided into 3 daily doses. Treatment was continued for 24 weeks. Blood tests, QOL measures, and levels of plasma CoQ and vitamin E were obtained at baseline and at 8, 16, and 24 weeks. Mixed-effects models were used to assess treatment differences in outcomes over time. Results: Between September 2004 and March 2009, 236 women were enrolled. Treatment arms were well balanced with respect to age (range, 28-85 years), pathologic stage (stage 0, 91%; stage I, 8%; stage II, 1%), ethnicity (white, 87%; black, 11%; Hispanic, 2%), and planned therapy. Baseline CoQ levels in the CoQ and placebo arms were 0.70 and 0.73 μg/mL, respectively; the 24-week CoQ levels were 1.83 and 0.79 μg/mL, respectively. There were no significant differences between the CoQ and placebo arms at 24 weeks for scores on the Profile of Mood States-Fatigue questionnaire (least squares means, 7.08 vs 8.24, P = .257), the Functional Assessment of Chronic Illness Therapy-Fatigue tool (37.6 vs 37.6, P = .965), the Functional Assessment of Cancer Therapy-Breast Cancer instrument (111.9 vs 110.4, P = .577), or the Center for Epidemiologic Studies-Depression scale (11.6 vs 12.3, P = .632). Conclusions: Supplementation with conventional doses of CoQ led to sustained increases in plasma CoQ levels but did not result in improved self-reported fatigue or QOL after 24 weeks of treatment.