How Sleep Apnea May Cause Cancer

When I first wrote my book, Sleep, Interrupted in 2008, I had a question mark in my diagram linking obstructive sleep apnea to possible cancer. Since that time, there have been a number of studies making that link stronger, and I am now more comfortable in removing that question mark. One of the basic hallmarks of obstructive sleep apnea is repeated episodes of low oxygen levels (intermittent hypoxia) due to obstructed breathing at night. If you google “intermittent hypoxia and cancer” you’ll see about 460,000 search results, of which 33,000 are scholarly articles. Low oxygen levels are strongly associated with cancer progression.

In a recent review article on this subject, Dr. David Gozal and colleagues published a paper titled, Sleep apnea awakens cancer: A unifying immunological hypothesis. They hypothesized that intermittent hypoxia and sleep fragmentation can promote changes in the tumor microenvironment, leading to a weakened immune system and tumor growth enhancement.

Its important to remember that intermittent hypoxia not only can enhance cancer development, it can also in theory enhance benign tumor growth as well. One of many possible explanation is the concept of increased levels of vascular endothelial growth factor, which enhances more blood vessel growth, so that more nutrients (via blood) can reach the oxygen starved tissues. Initially, it may only cause localized enlargement of the soft tissues. Imagine if you continue to have intermittent hypoxia, and let’s say that you have a gene that makes you more susceptible to cancer.  If you add additional lifestyle habits such as smoking and drinking alcohol, then one mutation can potentially lead cancer.

To date there hasn’t been any particular cancer that’s strongly associated with obstructive sleep apnea. However, one large-scale population study found that your chances of dying from cancer increases almost 5 times if you have untreated severe obstructive sleep apnea. Another study found a 2.5 times increased risk of having cancer and 3.4 times higher risk of dying from cancer with untreated moderate to severe obstructive sleep apnea. 

Notice that the most common types of cancer happen in the “low priority” organs when you’re under stress. These areas include the gastrointestinal system, the reproductive organs, hands, feet, and the skin. In general, the core, central areas take priority. Any form of physiologic or emotional stress diverts blood flow and nervous system activation away from low priority to high priority areas. Rarely do you hear about cancer in the brain, heart or muscles, which are considered high priority.

This is another example of how sleep connects the dots between almost every known chronic health condition. Unfortunately, cutting edge cancer research focuses mainly on the molecular, genetic, and biochemical aspects without looking at the big picture. Without addressing proper sleep and breathing, even the best cancer treatments can give possibly suboptimal results.

If you have a diagnosis of obstructive sleep apnea, do you have a cancer history in your family? 

Please note: I reserve the right to delete comments that are offensive or off-topic.

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2 thoughts on “How Sleep Apnea May Cause Cancer

  1. But is it the hypoxia which results from actual low blood oxygen levels as would be measured if we set a sensor in a major artery or is it the hypoxia which results from a vascular and local cell stress reaction compounded by a rapid fall of the carbon dioxide blood gas levels resulting in further vascular contraction and oxygen transport frustration?

    There are, after all, along with the sleep apnea very large changes in the chemoreflexes.

    From trying it many times I know that at my computer if I attach one of my pulse oximeters to my finger, note the SpO2 reading and then at the end of a simple exhale stop breathing for 30 seconds, well if there is a change in the SpO2 reading it may go up a percent or down a percent and maybe even two percent but even in the following thirty seconds after resuming breathing never more than a two percent change.

    The world record for under water breath holding is twenty two minutes[1]. If consciousness is expected to be lost at around 50% blood oxygen saturation then if the person started at 100% saturation the rate of loss to stay above 50% at the twenty two minute mark would need to be less than 2.3% per minute.

    Simply I wonder if the very rapid (by comparison) changes in “blood oxygen” levels measured at the finger tip (an extremity of an extremity) during sleep apnea events are not more representing a very local change in circulation and metabolism which stem from recent stress hormone release and breathing overshoot rather than actual changes in the blood oxygen levels in the main arterial supply.

    The result is the same. The cells do not get their needed oxygen. And cell function deficits are likely to bring forth cancer and other disease and apparently do. But perhaps the real cause of the oxygen deficit stems from the bodies over reaction to the air supply being cut off periodically rather than what happens during the actual time that the air was cut off.

    [1] http://www.guinnessworldrecords.com/world-records/1000/longest-time-breath-held-voluntarily-%28male%29

  2. I’d assume the most common link is breast cancer, simply because of its pervasiveness and because OSA is so strongly linked to metabolic syndrome. My mother had breast cancer.

    Speaking of other chronic conditions, has CPPS ever come up? I didn’t see it mentioned in the book but my PT mentioned that she sees a strong correlation between TMJ and CPPS. I suspect OSA may be to blame. The link to TMJ problems is straightforward, through bruxism. I hypothesize the link to CPPS is through nocturnal enuresis, a common symptoms of untreated sleep apnea. Holding urine nightly over years takes its toll eventually in terms of chronically tense pelvic muscles. That then leads to the other reproductive problems commonly seen in OSA patients. Check out the book “A headache in the Pelvis” if you get a chance. Like OSA, most doctors are still largely unaware of the condition and what causes it so it’s not surprising that the link hasn’t been made yet.