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Cortisol
How Sleep Affects Cancer - Poor Sleep Alters Hormones That Influence Cancer Cells
By Sid Kirchheimer
Reviewed By Michael Smith, MD on Wednesday, October 01, 2003
WebMD Medical News
Oct. 1, 2003 -- A new study shows that how well you sleep may
determine how well your body fights cancer -- and may help explain how
mental well-being plays into cancer recovery and progression.
After analyzing previous studies, Stanford University psychiatrist
David Spiegel, MD, and colleague Sandra Sephton, MD, say that sleep
problems alter the balance of at least two hormones that influence
cancer cells.
Sleep, Hormones, and Cancer
One is cortisol, which helps to regulate immune system activity
-- including the release of certain "natural killer" cells that help
the body battle cancer. Cortisol levels typically peak at dawn, after
hours of sleep, and decline throughout the day.
Spiegel tells WebMD that night shift workers, who have higher rates
of breast cancer than women who sleep normal hours, are more likely to
have a "shifted cortisol rhythm," in which their cortisol levels peak
in the afternoon. At least two studies show those women typically die
earlier from breast cancer. "We also found that people who wake up repeatedly during the
night are also more likely to have abnormal cortisol patterns," he
says. Cortisol is the so-called "stress" hormone triggered, along
with others, during times of anxiety and may play a role in the
development and worsening of cancer and other conditions.
The other hormone affected by sleep is melatonin. Produced by the
brain during sleep, melatonin may have antioxidant properties that help
prevent damage to cells that can lead to cancer. In addition, melatonin lowers estrogen production from the
ovaries. Thus, a lack of sleep leads to too little melatonin. This
series of events may expose women to high levels of estrogen and may
increase the risk of breast cancer. Spiegel says that women shift workers who are up all night produce less melatonin.
"There's a definite hormonal pattern that is affected by sleep
that in itself, can predict a more rapid progression of cancer," he
tells WebMD. "Getting a good night's sleep is fairly simple, if you allow
yourself to do it. The big problem for cancer patients is they take too
much on themselves and don't give enough time to help their bodies cope
with the illness. They're worried about burdening their families and
fulfilling their usual obligations." And that's the real message of his study, in the October issue
of Brain, Behavior and Immunity. It indicates the importance of good
sleep as one of several mind-body factors that might influence cancer
outcome. Sleep, Stress, and Cancer
Previous research, including some noted in Spiegel's study, shows
that cancer patients who manage their stress in group therapy, with
good social networks, or with regular exercise often fare better than
patients who don't manage stress effectively. "We know that people who are depressed or anxious have a
specific pattern of sleep disturbances. And if you had a bad night's
sleep, you don't handle stress as well," says Spiegel. Conversely,
those who better manage stress are more likely to have good sleep
patterns. Just last week, Swedish researchers said women under a lot of
stress may double their risk of breast cancer compared with those who
remain calm when life throws them a curveball. "My advice for cancer patients is to try to handle stress
well," says Spiegel. "By doing all the things your grandmother told you
to do -- eat well, sleep well, and get plenty of exercise -- you're
helping your body cope better with the disease." Does this mean that ensuring good sleep hygiene will become
the big thing in cancer treatment? No, says Len Lichtenfeld, MD, of the
American Cancer Society. "But is this important for people to remember? Yes," he tells WebMD.
"The bottom line of this report is that there is enough
information to take seriously the idea that how our bodies respond to
cancer is influenced by more than just the surgery, chemotherapy, or
radiation. It can be influenced by stress and sleep, and these are two
pieces in the puzzle that shouldn't be overlooked." --------------------------------------------------------------------------------
SOURCES: Sephton, S. Brain, Behavior and Immunity, October 2003;
vol 17: pp 321-328. David Spiegel, MD, the Jack, Lulu and Sam Wilson
Professor in the School of Medicine; associate chairman, department of
psychiatry and behavioral sciences, Stanford University Medical Center,
Stanford, Calif. Len Lichtenfeld, MD, deputy chief medical officer, the
American Cancer Society, Atlanta. WebMD Medical News: "Does Stress
Cause Breast Cancer?"
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