Melatonin may influence prostate cancer stage

By Sally Robertson, B.Sc.Jan 23 2014

A man’s risk of developing advanced stage prostate cancer may depend on how much melatonin he produces while he is asleep, suggest researchers.

Sarah Markt (Harvard School of Public Health, Boston, USA) and colleagues say their study showed a significantly reduced risk for the more aggressive form of prostate cancer in men with higher rather than lower levels of the sleep hormone.

“Because melatonin levels are potentially modifiable, further studies of melatonin and prostate cancer risk and progression are warranted,” stated Markt, who presented the findings at the ACCR-Prostate Cancer Foundation Conference on Advances in Prostate Cancer Research in San Diego, USA.

The deputy director of Prostate Cancer UK, Dr Matthew Hobbs, pointed out that more than 40,000 men are diagnosed with prostate cancer every year in the UK and that “improving our ability to distinguish which of those men are at risk of aggressive cancer that is likely to spread to other parts of the body from those who have low-risk cancer is of crucial importance as it would enable both groups to make better decisions about their treatment options.”

Markt and colleagues studied 928 Icelandic men from the AGES-Reykjavik cohort between 2002 and 2009. The men provided morning urine samples at recruitment and also answered a questionnaire about their sleeping patterns.

Overall, 111 of the men were diagnosed with prostate cancer and, of those, 24 had the advanced, more aggressive form of the disease.

Across the entire study population, the median urinary level of the melatonin marker 6-sulfatoxymelatonin, was 17.14 ng/mL.

Markt and team report that men who had an above median urinary level of this marker were 75% less likely to have advanced prostate cancer than men who had levels below the median.

The results also showed that men who reported difficulty getting to sleep, staying asleep or who took medication to aid their sleep, had significantly lower levels of the marker in their urine than men who did not report sleep problems.

“Sleep loss and other factors can influence the amount of melatonin secretion or block it altogether, and health problems associated with melatonin, disrupted sleep, and/or disruption of the circadian rhythm are broad, including a potential risk for cancer,” explained Markt.

"Further prospective studies to investigate the interplay between sleep duration, sleep disturbance, and melatonin levels on risk for prostate cancer are needed,” she says.