Effects of Melatonin on IL-6 Serum Level Changes and Fatigue Caused by Adjuvant Chemoradiotherapy in Breast Cancer Women: A Randomized Controlled Trial

Introduction: Cancer-related fatigue is one of the most common and debilitating complications of breast cancer. Cancer patients have been found to have lower levels of melatonin, and fatigue has been shown to be correlated with both melatonin and interleukin (IL-6) in cancer patients. This study aimed to evaluate the fatigue and serum level of IL-6 in response to melatonin treatment in breast cancer patients. Methods: In this double-blinded clinical trial, 74 women with breast cancer were evaluated for the effect of melatonin on fatigue induced by adjuvant chemotherapy and radiotherapy. The intervention group (n = 38) started receiving 6 mg of oral melatonin from 6 to 7 days before the start of adjuvant therapy until the disease progression, while the control group (n = 36) received a placebo during this time. The fatigue scores and serum IL-6 levels of both groups were measured at baseline and after the intervention, and the changes were compared. Results: The mean age of participants in the control group was 46.05 ± 10.55 y, and that of the intervention group was 50.47 ± 10.79 y (P = 0.223). The mean postintervention fatigue scores for the placebo and melatonin groups were 52.61 ± 4.57 and 25.16 ± 15.86, respectively (P < 0.001). There was no difference in the mean IL-6 level between the groups (P = 0.721). Conclusion: Administering melatonin in women with breast cancer undergoing adjuvant chemotherapy and radiotherapy leads to a significant reduction in fatigue but does not affect serum IL- 6 levels.