Three-year study of patients with advanced (stage 3 or 4) non-small cell lung cancer receiving treatment with chemotherapy drugs. Patients were divided into three groups:

Chemotherapy + 20 mg of melatonin at 8 AM
Chemotherapy + 20 mg of melatonin at 8 PM
Chemotherapy + Placebo

Results: Overall survival: the placebo group had a median survival of 10.4 months, while the nighttime melatonin group had a median survival 40% longer, 17.6 months.

After three years, 14-18% of the melatonin groups were still alive, versus only 3% of the placebo group.

Sleep quality was linked to survival –the better the sleep quality score, the better the survival rate, which supports previous findings that cancer patients with disrupted circadian rhythms have a poorer than expected lifespan.