Purpose
To examine the effects of melatonin supplementation on sleep, mood, and hot flashes in postmenopausal breast cancer survivors.
Methods
In a randomized, double-blind, placebo-controlled study, 95 postmenopausal women with a prior history of stage 0-III breast cancer who had completed active cancer treatment (including hormonal therapy) were randomly assigned 1:1 to either 3 mg oral melatonin (n=48) or placebo daily (n=47) for 4 months. Sleep, mood, and hot flashes were assessed at baseline and four months via self-administered questionnaire using the Pittsburgh Sleep Quality Index (PSQI), Center for Epidemiologic Studies – Depression (CES-D), and the North Central Cancer Treatment Group (NCCTG) hot flash diary, respectively.
Results
Eighty-six women (91%) completed the study and provided pre and post questionnaires. At baseline, 52% of participants reported poor sleep in the month prior to enrollment. Compared to subjects on placebo, subjects randomized to melatonin experienced significantly greater improvements in subjective sleep quality as measured by the PSQI, including domains on sleep quality, daytime dysfunction and total score. For example, the mean change in PSQI score was −0.1 in the placebo group compared to −1.9 in the melatonin group (p<0.001). There were no significant differences in measures of depression or hot flashes.
Conclusions
Sleep disturbances are common among breast cancer survivors, even after completion of active cancer treatment. This is the first randomized placebo-controlled study among breast cancer survivors to demonstrate that melatonin was associated with an improvement in subjective sleep quality, without any significant adverse effects.