AACR: Randomized trial of oral melatonin supplementation in breast cancer survivors

April 30, 2010

Melatonin supplementation in breast cancer survivors may improve quality of sleep, but not symptoms related to depression or biomarkers associated with breast cancer, according to a study presented at the 2010 American Association for Cancer Research (AACR) Annual Meeting.  The International Agency for Research and Cancer and the World Health Organization has classified night shift work as a probable carcinogen due to its effect on the melatonin pathway.  To evaluate the effect of melatonin, a double-blind randomized clinical trial was conducted in 95 postmenopausal women with a prior history of breast cancer (i.e., stages 0 to 3) who had completed their cancer treatment including hormonal therapy.  For 4 months, women were randomized to receive melatonin or placebo.  Endpoints of the trial included changes in breast cancer biomarkers, sleep, hot flashes, and mood.  At 4 months, no grade 3/4 toxicities were observed in women taking melatonin.  There was no statistically significant difference between the two groups for hot flashes, symptoms related to depression, and biomarkers (i.e., estradiol, IGF-1, IGFBP-3, or IGF-1/IGFBP-3 ratios).  But women in the melatonin group had improved scores in quality of sleep, sleep duration, and total sleep compared to women in the placebo group.  The effects of longer courses of melatonin are unknown as well as effects on premenopausal women.