Turn the Lights Out on Breast Cancer
Remarkable new research shows that it's crucial for women undergoing treatment for breast cancer to sleep in total darkness. Experts think that's because even the smallest amounts of light at night can shut down the production of the "sleep hormone" melatonin. Melatonin in produced by the pineal gland, a small structure that's inked to the brain. It's located between and slightly behind the eyes. Often called the third eye, the internal pineal gland is extremely sensitive to light. In complete darkness it releases melatonin, setting the stage for restorative sleep. Melatonin is a powerful antioxidant compound that is credited with repairing cellular damage that accumulates throughout the day. It's thought to repair damaged DNA, for example, making it especially important for helping prevent cancer.
Tulane University School of Medicine cancer researchers reported recently that light at night interrupts the release of melatonin, and renders the anti-cancer drug, tamoxifen, ineffective. Light at night allowed breast cancer cells to resist the effects of tamoxifen. In a press release, co-principal investigator, David Blask said, "High melatonin levels at night put breast cancer cells to 'sleep' by turning off key growth mechanisms. These cells are vulnerable to tamoxifen. But when the lights are on and melatonin is suppressed, breast cancer cells 'wake up' and ignore tamoxifen."
This illustrates, yet again, why sleep is so crucial to overall good health. Far from being "wasted" time, sleep allows the body to effect crucial repairs and tend to general maintenance tasks. This groundbreaking new study could lead cancer experts to identify light as an independent risk factor for developing resistance to cancer fighting drugs, including tamoxifen. The finding dovetails with previous research, which has shown that women who work nights—where they are exposed to light all night—tend to be at greater risk for developing breast cancer.
Robert T. Dauchy et al. Circadian and Melatonin Disruption by Exposure to Light at Night Drives Intrinsic Resistance to Tamoxifen Therapy in Breast Cancer. Cancer Research, July 2014 DOI: 10.1158/0008-5472.CAN-13-3156