A new study has found that light exposure at night causes a commonly used drug for breast cancer to be ineffective.
“Circadian and Melatonin Disruption by Exposure to Light at Night Drives Intrinsic Resistance to Tamoxifen Therapy in Breast Cancer,” a study in Cancer Research, was conducted by cancer researchers at Tulane University School of Medicine, and is the first to find a link between the success of the drug tamoxifen treating breast cancer and melatonin.
The study included the use of rats, in which human breast cancer cells were implanted. Rats were kept on a schedule of 12 hours light exposure followed by 12 hours of total darkness for several weeks. In the next phase of the study, the same light/dark schedule was applied except during the 12 hours of darkness, the rats were exposed to dim lighting (mimicking lighting coming from underneath a door in a dark room).
The results showed that melatonin delayed tumors growth and formation by itself, but combined with tamoxifen there was a dramatic regression in the rats exposed to total darkness or receiving melatonin supplements.
Melatonin is a hormone that helps make us sleepy and stay asleep at the right time. Exposure to light, especially blue light emitted from electronics halts the production of melatonin, making for a night of poor sleep and very long next day.
The significance of these findings is one that can’t be ignored for those being treated with tamoxifen and are consistently exposed to light due to an overnight or rotating work schedule, use of electronics during night hours or sleep issues.
It is critical that we all make sure to stay away from electronics at least an hour before bed to allow for deeper sleep and to keep our biological clock in sync and healthy. If you are having trouble sleeping, always consult with a licensed physician as soon as possible!