A Randomized, Controlled, Parallel-Group, Trial on the Long-term Effects of Melatonin on Fatigue Associated With Breast Cancer and Its Adjuvant Treatments

OBJECTIVE: Cancer related fatigue is a distressing condition and correlated with decrease in quality of life of patients with malignant conditions. In continuation of our previous research, we assessed long term anti-fatigue effects of melatonin in patients with the breast cancer. MATERIAL AND METHODS: In this clinical trial, 92 breast cancer patients were randomly assigned to receive either melatonin (18 mg/day) or placebo from 1 week before the adjuvant treatments until 2 years after their completion. The levels of fatigue were assessed before and after intervention using Brief Fatigue Inventory (BFI) and were compared at a significance level of P ≤ .05. RESULTS: The BFI scores were similar between the 2 groups at the baseline (placebo group: 5.56 ± 1.59 and melatonin group: 5.72 ± 1.68, P = .67). After the intervention, not only the mean fatigue score was significantly lower in melatonin group (2.93 ± 1.04 vs 1.99 ± 1.02, P < .001, P ≤ .05), but also a greater reduction in fatigue score in intervention group was evident over time (P ≤ .001). CONCLUSION: Long-term usage of melatonin even after completion of adjuvant therapies in women with breast cancer decreased the levels of fatigue associated with the malignant condition and its treatments. THE TRIAL REGISTRY NAME AND URL, AND REGISTRATION NUMBER: Iranian Registry of Clinical Trials, https://en.irct.ir/trial/62267, IRCT20180426039421N3