Is sleep a time of restoration or deterioration? We often think of sleep as the time in which our body regenerates. For some time, rest and regeneration have been explicitly linked. When we feel ill one of the first things that we think to do is to go to bed early, sleep in, or, at the very least, take a nap. When we wake, we feel refreshed and ready to take on the world once more.
A new study, recently published in Nature, says that breast cancer cells shed from their original tumors and spread—or metastasize—more rapidly as patients slept.  When cancer cells metastasize to other parts of the body, they begin to form new tumors in the organs of their new destination.
Test subjects in the study, both human and mice, were recorded to have significantly higher levels of circulating tumor cells (CTCs) during sleep.  Metastatic tumors are notoriously difficult to treat. In fact, metastasis is the leading cause of death among cancer cases and has been proven resistant to traditional cancer treatments.  This possibly means that in the case of treating metastatic tumors, stopping the tumor cells from spreading in the first place could be key.
Now, this isn’t meant to scare cancer patients from getting some much-needed shut-eye. The study aims to be able to track and target the spread of these nomadic cells to put a stop to them before they set up camp somewhere else. Think of it like having the battle plans from an enemy army. If you know they are coming at night, you won’t wait until after breakfast to counterattack. Prevention is an invaluable part of any treatment.
Despite this interesting finding, more studies are needed to solidify the connection between the proliferation of CTCs and our circadian rhythm.
1- Breast cancer cells are more aggressive during sleep. Science. https://www.science.org/content/article/breast-cancer-cells-are-more-aggressive-during-sleep
Accessed July 13, 2022.
2- Alejandra Manjarrez. While the body rests, breast cancer spreads more aggressively. The Scientist Magazine®. https://www.the-scientist.com/news-opinion/while-the-body-rests-breast-cancer-spreads-more-aggressively-70164 Accessed July 13, 2022.
3- Qian C-N, Mei Y, Zhang J. Cancer metastasis: Issues and challenges. Chinese journal of cancer. file:///Cancer Metastasis/ Issues and Challenges Published April 3, 2017. Accessed July 13, 2022.
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