The Breast Cancer Sleep Disorder Connection

PJ Hamel Health Guide
  • Remember when you were a kid growing up, and sleep was as easy as 1-2-3? One, you took a bath. Two, Mom read you a story and kissed you goodnight. And three, you dropped off to sleep, fuzzy teddy bear held close to your heart. Life was so simple then!

    Now, night after night you find yourself tossing and turning in bed, wondering what’s become of the peaceful haven it used to represent. Turn off the light, pull up the covers, close your eyes, and fall asleep; that’s all there was to it, back before cancer, right?

    Oh sure, we’ve all experienced wakeful nights now and then, even for significant periods of our lives. Infants live on a feeding schedule that leaves us begging for two solid hours of sleep; teenagers routinely tramp in at midnight or later, and being moms, we’re never really fully asleep till we hear the car pull into the driveway, or the door open. But now, for no apparent reason, we stay awake, night after night after night, at a time when we’ve never craved sleep so much. What’s the deal?

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    Scientists studying the cancer/sleeplessness connection believe the heart of the matter lies in the circadian rhythm, a deep-seated cycle of sleeping and waking that’s inherent in nearly all living organisms. Not only does the body possess an overall rhythm; each cell has its own rhythm, as do the liver and kidneys. Mainly based on light and darkness, the circadian rhythm tells us when to sleep, and when to be awake. Cells in the eye’s retina signal the brain, which hosts its own “biological clock.”

    When it gets dark, the brain releases melatonin, a hormone that tells the body it’s time to sleep. The level of melatonin gradually decreases as time goes on, and then levels off at dawn, when your eyes again signal your brain, this time that it’s time to wake up. This powerful rhythm can be tampered with, but at a cost: witness the fatigue of jet lag, and the difficulties faced by workers moving from the day shift to the night shift. Now, studies seem to show that the same genes that help regulate the circadian rhythm also sometimes negatively affect a particular tumor suppressor gene. Studies also show that more women working the night shift get breast cancer than women working days. Is there a connection here?

    Since the circadian rhythm regulates sleep, and sleep (or lack thereof) affects the immune system, scientists have begun to examine the best way to deliver cancer treatments, particularly chemotherapy, in harmony with the patient’s circadian rhythm. Since blood pressure, digestion, and other bodily activities also fall under the circadian sway, it may be that chemotherapy is more effective at different times of the day, patient by patient. This new area of study, called chronotherapy, may someday increase chemo’s effectiveness, simply by delivering it at the “right” time of day.

    Well, this is all fine and good, you say. But what am I going to do about my sleep problems? There are things that can help, both chemical (drug), and behavioral. Next time we’ll take a look at a number of different ways to get some much-needed shut-eye.

Published On: February 13, 2007