A randomized, placebo-controlled trial of melatonin on breast cancer survivors: impact on sleep, mood, and hot flashes

Randomized, double-blind, placebo-controlled trial. 95 postmenopausal women with a history of breast cancer (stages 0-III) who had completed active cancer treatment; randomized to melatonin (n=48) or placebo (n=47).

3 mg oral melatonin taken nightly at 9 p.m. for 4 months.

Melatonin significantly improved sleep quality vs placebo on the Pittsburgh Sleep Quality Index (PSQI) after 4 months: mean PSQI change −1.9 with melatonin vs −0.1 with placebo (p<0.001). Improvements were in sleep quality and daytime dysfunction; no significant differences in depression (CES-D) or hot flashes. Sleep disturbances are common among breast cancer survivors; melatonin appears to be a safe, tolerable option to improve sleep in this population.

Not specifically recruited for sleep disorders; four-month duration; not powered for depression or hot flashes; 9.5% overall attrition with some toxicity-related dropouts; hot-flash analyses limited by small baseline sample; single-center study; melatonin sourced from a single supplier; generalizability to active-treatment populations uncertain.