Crews & Cancer

[Jaydee]

October 22, 2003

New research released Wednesday shows airline flight crews had a higher than normal rate of skin and breast cancer.

Researchers at the University of Iceland in Reykjavik found that flight attendants who had worked for five or more years were more likely to develop breast cancer.

And in a separate study, scientists at the Stockholm Centre for Public Health in Sweden uncovered an increase in malignant melanoma, the deadliest form of skin cancer, among both male and female cabin crew.

Previous studies have also suggested that skin cancer and possibly acute myeloid leukaemia were more common in male pilots and that female flight attendants had a raised risk of breast cancer.

"There is mounting evidence that cabin crew appear to have an increased risk of malignant melanoma and breast cancer," Dr Elizabeth Whelan of the Centers for Disease Control and Prevention (CDC) in the United States said in a commentary on the research studies published in the journal Occupational and Environmental Medicine.

Whelan said higher doses of cosmic ionising radiation were found at higher altitudes. Doses that flight crews are exposed to have been increasing over time as longer flights at higher altitudes have become more common.

But she said more research was needed to determine whether the increased cancer risk is due to work or other lifestyle factors. Further studies being done in the European Union and the United States might provide more answers, Whelan added.

(Reuters)

[Guest 1pawn]

http://content.health.msn.com/content/article/74/89362.htm?pagenumber=1

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.

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?"

[DEFCON]

There are also a number of studies that contradict this one. Study results such as this represent a very small piece of a very large puzzle. The study results are quite interesting though.