Sleep Apnea and Breast Cancer: Is There A Connection?
Posted Nov 23 2009 10:01pm
There’s been a lot of press coverage recently about the new mammography screening recommendations for breast cancer. The United States Preventive Service Task Force recently recommended that women begin routine mammography screening at age 50, rather than 40. This is an important issue for me as my aunt died from metastatic breast cancer in her early 40s.
One thing that I see over and over again is how obstructive sleep apnea can affect every aspect of your health, from your mood, to diabetes, to heart disease. You may think that cancer and sleep apnea are totally separate conditions, but with the human body, everything is ultimately connected in one way or another. This lead me ask the question: Do sleep apnea and cancer have a common origin?
In my practice, anytime I see a patient with a history of breast cancer, I almost consistently see the following: cold hands or feet, unrefreshing sleep, an inability to sleep on their backs, and a severely snoring parent, typically with cardiovascular disease. What’s remarkable is that when I examine their airways with a fiberoptic camera, the space behind the tongue is usually very narrow, especially when they lie flat on their backs. This anatomy leads to repeated obstructions and arousals, especially when sleeping on their backs and in deep sleep, when muscles relax the most. For this reason, these women prefer not to sleep on their backs.
In my book, Sleep, Interrupted, I describe a process where due to poor breathing and inefficient sleep, a physiologic stress state is created, which leads to lack of proper blood flow to certain parts of the body that are considered unimportant when you’re in a fight or running from a tiger. These areas include the digestive system, reproductive organs, your hands and feet, and your skin, amongst others.
During periods of stress (whether internal/physiologic or external/emotional), there can be severe blood flow restriction to any of these body areas. As an example of how dramatic this can be, there’s a description of a man who was severely injured during battle, and most of his abdominal wall was missing, with his bowels clearly visible. While he was recovering in bed, his doctors noticed that whenever he was angry or in pain, his bowels were dark and dusky, whereas when he was happy, his bowels looked pink and healthy. Similarly, there can be dramatic fluctuations in blood flow to the breasts depending on the woman’s mood and stress-inducing states.
One common finding in both cancer and sleep apnea research fields is that hypoxia (lack or oxygen) in tissues can lead to production of signals that tell the body to bring in more blood and nutrients. As a result, a number of inflammatory mediators are released, including the well-known vascular endothelial growth factor (VEGF). VEGF promotes local growth of blood vessels in oxygen-poor areas. Imagine if this process happened all the time, with slow but gradual growth of local tissues, with activation of genes and proteins that promote more inflammation and more cell reproduction.
We know that chronic overstimulation of any tissue can lead to cell replication that can go out of control. Chronic overstimulation of breast tissue can initially lead to localized benign growths or cysts, and some of these can end up transforming into malignancies. Perhaps some women with certain genes may be more susceptible to this transformation. This same process can also be described for prostate cancer.
Most younger breast cancer survivors probably won’t have obstructive sleep apnea if tested. But what they most likely will have is upper airway resistance syndrome, which results in multiple microscopic obstructions and arousals that prevents deep, efficient sleep. This can cause the nervous system to become hypersensitive, with increased physiologic states of stress. As they gain weight later on in life, many will progress into formal sleep apnea.
Studies show that breast cancer survival is poorer in obese patients. Similar findings are also found with prostate cancer. This is possibly explained by the fact that the more obese you are, the more likely you’ll have obstructive sleep apnea. Having obstructive sleep apnea significantly increases your risk of dying in general.
Granted, what I’m describing here is a very different perspective in explaining breast cancer, and is sure to be controversial in some people’s minds. However, rather than trying to explain breast cancer from a molecular, genetic, or organ level, wouldn’t you agree that it’s much more satisfying when you can explain this illness from a whole-person perspective? As much as Western medicine tries to deny it by fragmenting care to different specialties, we know intuitively that whether it’s the breast, the heart, the mind or the prostate gland, everything is ultimately connected.
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