Poor and insufficient sleep may contribute to cancer risk. Sleep-related physiology can help to treat cancer more effectively. But what happens to sleep when you’re living with cancer? What are the sleep risks people with cancer face? And how can protecting daily sleep affect treatment and recovery? That’s what I’ll talk about in this last installment of my sleep and cancer series. You can catch up on previous installments, here, here and here.
How cancer interferes with sleep
Both the presence of cancer and its treatment can often lead to major sleep problems, including in people without a history of sleep troubles. People with cancer often struggle to get enough sleep, and to maintain a normal sleep routine. They cope with excessive, sometimes debilitating fatigue. They’re at greater risk for developing symptoms of sleep disorders, including insomnia, hypersomnia, restless leg syndrome and obstructive sleep apnea.
The physical pain and emotional distress that accompanies cancer can also be deeply disruptive to sleep. And medications themselves—whether those that target cancer or the secondary conditions that can develop in people undergoing cancer therapy—often have side effects that can create significant sleep issues.
That’s a lot of risk to sleep to deal with, on top of a cancer diagnosis. Let’s take a closer look at some of the most significant issues people with cancer face during treatment.
Radiation and chemotherapy come with a long list of potential sleep problems. Nausea, night sweats, and pain are common physical side effects of these cancer therapies, and they all can make it difficult to get a decent night’s rest. These common cancer treatments can also give rise to secondary medical conditions, such as hypothyroidism and anemia, as well as changes to hormone levels, all of which may come with their own sets of sleep troubles.
Patients undergoing radiation or chemotherapy may also experience a strong need to sleep during the day as well as at night. This excessive sleepiness is known as hypersomnia, it’s among the most common cancer-related sleep problems. Symptoms of hypersomnia include:
- Sleeping more than 10 hours in one stretch
- Having difficulty staying awake during the day
- Experiencing feelings of sleepiness that don’t go away, no matter how much sleep you get
Hypersomnia can be related directly to some types of cancer, including cancers of the brain and central nervous system, as well as to cancer that has spread to the brain from other parts of the body. Chemotherapy and radiation treatments can also bring about hypersomnia, as can medications that cancer patients also often rely on, including anti-nausea medications, drugs for pain, and anti-depressant or anti-anxiety medications.
(I wrote about the possible health hazards associated with hypersomnia, here.)
Feeling the need to sleep a lot is far from the only form of disordered sleep that cancer patients face. Symptoms of insomnia are also common in people with cancer. Studies have found that about a third or more of people undergoing cancer treatment cope with insomnia symptoms, including:
- Difficulty falling asleep
- Trouble staying asleep, i.e., waking frequently throughout the night
- Waking very early in the morning
- Feeling unrefreshed by sleep
Cancer-related insomnia can arise as a side effect of chemotherapy or radiation treatment, or from secondary health conditions linked to cancer, as well as the medications used to treat those conditions. Hospital stays can also trigger insomnia symptoms. A 2017 study looked at the onset of insomnia in people who were hospitalized. (The study participants had no previous history of insomnia.) Scientists found that more than a third of people developed some symptoms of insomnia. The reasons included the disruptions of nighttime vital sign check-ins, the noise and light of the hospital environment, as well as patients’ own medical conditions. The routines of a hospital stay, with round-the-clock checks, and lights and sounds, can be extremely disruptive to sleep-wake cycles and circadian rhythms.
This study wasn’t specific to cancer patients, and many of the patients in this study saw their insomnia symptoms recede after their hospital stays were over. Unfortunately, insomnia and other sleep issues can linger over the long-term in people who’ve been treated for cancer—more on this in a moment.
While there is widespread acknowledgement that people undergoing cancer treatment experience frequently and often severely disrupted sleep, we don’t know nearly enough about the prevalence of sleep disorders in cancer patients. As this recent study points out, investigations have tended to focus more on symptoms of disrupted sleep, and less on rigorous assessments of underlying sleep disorders. We need more research into the presence of clinical sleep disorders in people with cancer.
Sleep and the psychological challenges of cancer
Facing a cancer diagnosis and treatment is an anguishing and stressful emotional experience for many people. Anxiety and depression don’t occur in all cancer patients, but these conditions do often occur in people living with cancer. Anxiety and depression also often go hand in hand with sleep problems, including a need to sleep excessively, difficulty sleeping, and disrupted sleep-wake cycles. Cancer-related sleep problems are strongly linked to emotional distress. In some cancer patients, a complex and difficult cycle develops, in which poor sleep and emotional distress exacerbate one another, and also contribute to fatigue and to an increased sensitivity to physical pain.
Another sleep problem that’s associated with cancer and its treatment? Nightmares. The emotional stress and upheaval of cancer may often be a cause of more frequent and more intense nightmares and vivid dreams in people with cancer. But nightmares can also be triggered by medications used in cancer treatment, including pain medications and anxiety medications. The presence of physical pain itself can also lead to more disturbing dreams.
Not every cancer patient will experience nightmares or more vivid and intense dreams. But among those who do, these disturbing dreams can create a lot of additional anxiety, for both waking life and sleep itself. Nightmares can compound a person’s sleep issues, heightening anxiety at bedtime, causing nighttime awakenings and a difficult return to sleep. Addressing nightmares and disturbing dreams that negatively impact sleep is every bit as important as tending to any other sleep issues that arise for cancer patients and survivors.
Long-term sleep problems in cancer survivors
Research increasingly indicates that, for some cancer survivors, sleep problems and sleep disorders can pose long-term health challenges. In one study of sleep disturbance in cancer patients, more than three-quarters of patients with insomnia had the sleep disorder for six months or more. Other research indicates that between 20 to 30 percent of cancer survivors may experience ongoing insomnia and fatigue that lasts a year or more.
A 2014 study found that among adult survivors of childhood cancers, 28 percent showed clinically significant signs of insomnia. A point of particular concern for me in this study? About two-thirds of these patients’ medical providers weren’t documenting issues about sleep in their patients’ notes. That suggests cancer survivors aren’t getting the long-term support and attention they need for their sleep issues.
Several factors can contribute to insomnia and other cancer-related sleep issues, including anxiety, depression, irregular sleep habits, and sleep-wake cycles thrown off by hospital stays and by extreme, persistent fatigue. When treatment ends, and when a patient enters remission, the effects of these factors can remain active over sleep. For example, hormonal changes can occur during cancer treatment that can create long-term changes to sleep that survivors may contend with for many years to come.
Insomnia in particular is a sleep problem that can become entrenched and take on a life of its own. For people who find themselves struggling to fall asleep, the act of going to bed may become a source of stress—and worry about sleep becomes itself an obstacle to rest.
Cancer survivors may also be at higher risk for obstructive sleep apnea and other forms of sleep disordered breathing. A study by scientists at Johns Hopkins found sleep disordered breathing in 19 percent of childhood cancer survivors—that’s a much higher rate than in children without cancer. Other research has found similar results, with higher rates of sleep-disordered breathing in cancer survivors than in the general population.
Research has linked the presence of OSA to higher risk for death from cancer.
It’s important for everyone, including cancer survivors, to know—and be prepared to promptly address with their physicians—the symptoms of OSA. The most common OSA symptoms include:
- Snoring, especially loud and chronic
- Gasping for air, and sounds of choking or snorting, sometimes resulting in abrupt awakenings
- Excessive sleepiness during the day
- Trouble with memory and concentration
- Waking with a dry mouth or a sore throat
- Needing to get up frequently in the night to urinate
- Decreased libido
Healthy sleep is related to higher cancer survival
People living with cancer have a lot of health and treatment considerations to think about. It’s important that sleep be among them. Research shows that the ability to get the right amount of high-quality sleep may affect chances of survival in people with cancer. (It’s not only people with cancer who are affected in this way—it’s all of us. A strong body of research connects healthy sleep to lower all-cause mortality rates.)
A 2017 study found that both too little sleep (6 hours or less) and too much sleep (10 hours or more) were associated with a higher risk of death in patients with advanced cancer. Another study of patients with advanced cancer—this one published in 2018—also found short and long sleep associated with more severe cancer symptoms and lower survival rates.
Our sleep quality and quantity appear to matter to cancer survival before cancer is even diagnosed. A recent study found multiple sleep problems that were present before a cancer diagnosis were eventually linked to lower cancer survival rates. Both short sleep duration and snoring that occurred in people before they were diagnosed with cancer were associated with greater risks for cancer death. When the two sleep issues occurred together, the mortality risks grew even higher.
Sleep is one of many factors in treating and living with cancer. But it should never be overlooked. (Too often, even today, it often seems to be.) Treating sleep issues and addressing sleep concerns in an effort to maintain healthy rest can improve emotional resilience, enhance immune strength, and improve quality of life for people with cancer. It may also play a role in improving the chances of living long beyond a difficult diagnosis.
Michael J. Breus, PhD, DABSM
The Sleep Doctor™