Melatonin may have a role in the treatment of cancer, according to a new study published in the Journal of Pineal Research. Researchers say that the results are so compelling that cancer funding agencies should be eager to support clinical trials to evaluate its therapeutic role in a variety of cancers.

Melatonin is a hormone naturally found in humans which helps regulate sleep/wake cycles. Its association with cancer has been shown in many studies assessing links between shift work and cancer rates, and shown a consistent relationship. The association between melatonin levels and cancer progression has suggested to some that melatonin may be a modifier of cancer progression.

In this latest study, researchers examined all clinical trials assessing the role of melatonin as a therapy for solid tumour cancers. The authors reviewed 10 randomized clinical trials that included a total of 643 cancer patients with a variety of different solid tumour cancers. The types of cancers involved included lung, brain, skin, renal and breast cancer.

“In this analysis, the effects appeared to be consistent across studies” say the authors. The researchers examined the effect of large doses of melatonin (10-40mg/day) on survival rates at one year. Melatonin reduced the risk of death at one year by 34%.

“Effects this large certainly warrant further clinical trials” say the authors. The study also showed that melatonin was predominantly safe and had a beneficial effect on sleep patterns of patients.”

The study authors recommend patients discuss this with their physicians before beginning any treatments.

McMaster University, Nov 22, 2005