Introduction

We don’t hear much about the deep connection between cancer and sleep but that doesn’t mean it’s not there. Researchers have been studying this connection for years and the most recent results are fascinating.

When a person doesn’t sleep enough over the long-term, research shows that they raise their chances of getting certain types of cancers. This risk is exacerbated when they work a night shift for an extended period of time.

On the other side, many cancer patients experience significant sleep disturbances. They can struggle to fall asleep or stay asleep. This has many causes, including side effects from cancer drugs, pain and discomfort, and the stress of their illness.

There are many things that cancer patients can do to try and improve their rest so they can get the sleep they need. This allows the body to heal from chemotherapy and participate in fighting the cancer.

Lack of Sleep and Cancer: Is There a Connection?

Not getting enough sleep is unpleasant all the way around. People who don’t sleep well feel grumpy, are easily irritated, and find it hard to get through the normal tasks in their day. However, not sleeping doesn’t just feel bad, it’s also bad for the body. When people experience sleep disruptions over a long period of time, research shows that they have a higher chance of developing certain types of cancer.

Prostate and Colorectal Cancers Associated with Sleep Issues

A study from 2013 correlates both disrupted sleep and shortened sleep with a greater risk of developing prostate cancer. The men who developed cancer reported problems falling asleep, problems staying asleep, or simply choosing not to get enough sleep. The correlation was especially strong when the researchers looked specifically at cases of advanced prostate cancer. 

There is also a link between a lack of sleep and developing colorectal cancer, according to a study from 2010. In this study, people who slept less than 6 hours per night demonstrated a greater risk for a number of conditions, including an almost 50% greater risk of these cancers.

However, sleeping too long can raise the risk of colorectal cancer, too, especially if the patient has an underlying medical condition. People who slept more than 9 hours and snored or were overweight had a significantly higher chance of developing colorectal cancer, too. This suggests that sleep apnea may contribute to an increased cancer risk, though snoring subjects were not diagnosed with that condition. Interestingly, this study also found NO distinct correlation between less sleep and a higher risk of developing colorectal tumors.

Breast Cancer and Sleep Disruption

Sleep also affects a woman’s chances of getting breast cancer. In a study from 2012, women who reported sleep disturbances in the two years prior to being diagnosed with breast cancer had a greater risk of the cancer recurring. This indicates that women who regularly don’t get enough sleep may be at a higher risk for aggressive breast tumors.

Is Shift Work to Blame for Cancer Risk?

Studies also connect cancer to long-term shift work. Researchers reviewed available studies in 2012 and found a good case for a connection between shift work, or any circadian rhythm disruption, and prostate cancer. A study out of Spain in 2015 confirms this, showing a higher risk of prostate cancer among shift workers. Those who had a long-term exposure to shift work had a higher risk of developing the cancer, and they also tended to develop more aggressive forms of the cancer.

Working the night shift also raises a woman’s risk of developing breast cancer. A Danish study correlated frequent, long night shift work with an increased breast cancer risk, and found that risk even higher in women who preferred to get up early but had to work nights instead. A literature review from 2015 confirms this connection, stating that any long-term circadian rhythm disruption raises a woman’s chances of breast cancer.

A Chinese study from 2016 confirms the connection between shift work and cancer, demonstrating that men who had a long history of working night shifts, and who did not nap during the day, had a greater risk for developing cancer in general. This study also notes that men who slept more than 10 hours per night were at a greater risk for cancer.

Sleep, Shift Work, and Melatonin

Researchers are not sure of the mechanism by which lack of sleep raises cancer risk, but it is likely tied to melatonin production. In 2016, researchers found that treating certain types of breast cancer cells with melatonin seemed to slow or inhibit their growth, because less estrogen bound to those cells. Since melatonin is produced when people sleep, this begins to make sense of the connection between sleep and cancer.

Sleep and Cancer – An Unclear Association

While the link between sleep and cancer is disturbing, there is also reason for caution. A literature review performed in 2017 argues that there is no clear link between sleep disturbances and cancer. When these researchers examined methodology, study design, and assumptions researchers made, they found no clear statement regarding sleep and cancer risk.

There is likely enough evidence to suggest a link between sleep and cancer, though this has not been definitively proven. The field needs more research before we can draw any sure conclusions.

Insomnia, Cancer Fatigue, and Other Sleep Problems

There is not only a correlation between sleep issues and getting cancer but one between sleep issues and having cancer, too. In fact, 30%-50% of all cancer patients report having insomnia, and these rates are even higher in patients with breast or some sort of gynecological cancer.
These complaints are 2-3 times higher than they are in the general population, and cover all types of insomnia (inability to fall asleep, waking in the night, and waking extremely early). In cancer patients, the insomnia is frequent and long-lasting and has consequences for the patient’s daytime functioning.  

Many cancer patients also report high levels of fatigue, with some types of tumors causing exhaustion for over 80% of patients. Some of this fatigue can be tied to insomnia, though it can also come as a result of certain cancer treatments, like surgery, chemotherapy, radiotherapy, or immunotherapy.

Insomnia’s Impact on Cancer Patients

Source: The Oncologist, measuring the perceived fatigue in patients with cancer receiving radiotherapy. Intensity of fatigue was measured using a category ratio scale (CR10); “lack of energy” was evaluated using the Swedish Occupational Fatigue Inventory (SOFI); sleepiness was assessed using the SOFI and the Karolinska Sleepiness Scale (KSS).

Insomnia in cancer patients seems to come alongside depression, and possibly anxiety. This is important because both of these conditions can influence sleep outside of cancer, so it seems likely they play a part in a cancer patient’s insomnia, too. Treating the underlying condition may help the patient sleep better.

Insomnia in cancer patients also comes along with pain and can be worse when patients are hurting because of the cancer or its treatment. Those who suffered from sleep disorders before they had cancer are more likely to do so once they have cancer when they were compared to people who slept well before they were diagnosed.

Unfortunately, insomnia doesn’t seem to only affect cancer patients while they have cancer. Many develop poor sleep patterns right after being diagnosed or during active cancer treatment, which is the worst time for sleep for most patients. These patterns often continue after treatment is finished, though, diminishing patients’ quality of life until they are changed.

It’s not just the cancer patient who suffers disordered sleep, either. Families and caregivers also report sleeping poorly. They might sleep less often, have their sleep disrupted by the patient’s needs, or have unsatisfying sleep.

However, there is not a solid, validated way to measure sleep and sleep disturbances in either patients or their families, so it is difficult to tell how many patients and families suffer from sleep disturbances, how impactful these are on their lives, and how long they last. Insomnia or unsatisfying sleep could affect more patients than is currently thought, and the impact could be greater and longer-lasting than current studies have the capability of measuring.

Underlying Causes of Sleep Loss in Cancer Patients

There are many possible causes of sleep disturbances and insomnia in cancer patients and their caregivers. Stress and distress over having cancer and about cancer symptoms seem to be a significant cause of these sleep problems, though. One study showed that, even in a population where distress over symptoms was generally low, 30% of patients had insomnia related to their worry and concern.

The Patients Most Likely to Lose Sleep

The study mentioned directly above also shed some light on who is most likely to lose sleep because of stress. Those with more advanced stage cancer, women, and older patients were more stressed out and had higher rates of insomnia. In addition, patients with lung cancer were more stressed than those who had other types. Since less stress over symptoms and during treatment correlates with higher survival rates, it’s important to treat stress, and the insomnia that seems to come along with it, so patients have a better chance of getting back to normal life post-cancer.

Medications Can Harm Sleep

Cancer patients may also experience sleep disturbances due to the medications they are on for chemotherapy, or ones used to counteract some of the effects of those drugs. Steroids, for instance, make it harder for people to sleep and are often given to cancer patients to help them feel better. Medical personnel need to balance a patient’s need for a particular medication with their need for rest.

Cancer Fatigue and the Nap Interference

Because cancer patients often experience fatigue, it is common for them to take naps. If they sleep too much during the day, though, this can interfere with their ability to sleep at night. This could inadvertently lead patients to suffer from insomnia, simply because they are taking care of themselves during the day.

While the connection between having cancer and struggling with sleep is strong, there’s more research that can be done. It would help doctors and patients alike to have a deeper understanding of the physical mechanisms that make cancer a likely precursor of insomnia.

Beating Insomnia: Advice to Improve Your Sleep

No one who struggles with insomnia has to give up hope of getting the sleep they need. There are a wide variety of treatments and strategies available to help cancer patients (and the rest of us!) get the sleep that will help us survive and thrive, no matter what.

Note that, while there are medications available that can help with sleep, these come with their own difficulties, especially for cancer patients. Medications can be contraindicated because of other medications the patient is on, they can be addictive, and they can promote sleep that is not restful. They are generally the last resort for treating sleep issues, though they should be considered if nothing else works. There are plenty of things to try before medication becomes a necessary intervention for insomnia.

Cognitive Behavioral Therapy (CBT)

Cognitive Behavioral Therapy is a solution-based form of psychotherapy that works to change thoughts, behaviors, and emotions that are not working for the patient. It works to change patterns in the way people think, which changes the way they act and the way they feel. This type of therapy has been very successful in helping people overcome insomnia, especially cancer patients.

In addition, the effects of CBT in cancer patients seem to be long-lasting and correlate with a higher quality of life. CBT can also help patients improve mood and reduce feelings of fatigue, so it may be important for these people in more than one area of their lives.

There are several aspects of CBT that may be of especial utility in helping insomnia. Cognitive restructuring is the act of changing the way a person thinks. Patients learn how to notice their negative thoughts, determine whether the thought is accurate, test it in the real world, and replace those thoughts with more balanced ones. If stress is a major factor in insomnia for a patient, this is one of the best ways to tackle it.

Sleep Restriction Therapy

Another common CBT technique used to help fight insomnia and hypersomnia in cancer patients, Sleep Restriction Therapy evaluates how much a person is actually sleeping at night and sets wake and sleep times based on that. The sleeper must commit to going to bed and rising at these times for the duration of the therapy. Patients may not nap, either.

The patient holds to this regimen until he or she is sleeping the entire time they are in bed. If they feel fatigued during the day, they can increase the amount of sleep by 15 minutes. Gradually, they learn to sleep while in bed and they figure out how much sleep they need to function well.

Stimulus Control Therapy

This Cognitive Behavioral Therapy technique focuses on helping sleepers who have anxiety about sleeping due to fighting insomnia. People who use Stimulus Control Therapy commit to going to bed only when they feel sleepy, getting out of bed when they can’t sleep, using the bedroom only for sleep and sex, getting up at the same time every day, and not napping. Over time, this technique helps people learn how to rest again.

Meditation

Mindfulness meditation is another method used to help cancer patients sleep, especially when their lack of sleep is due to stress. This meditation involves focusing on the present moment. Practitioners do this for a set amount of time, anywhere from 10 minutes to several hours, gently refocusing themselves when they find their minds wandering. It is an effective way to reduce stress and promote relaxation.

A 2003 study determined that mindfulness meditation helped breast cancer patients get more sleep. Meditating is not as effective in combatting insomnia in cancer patients, however, as CBT. It may be the technique of choice when a patient is especially stressed or does not want to participate in CBT. It can also be used in addition to CBT techniques.

Yoga

Yoga, which is often tied to mindfulness, can be another effective method of combatting insomnia in cancer patients, though a regular practice may be difficult for those going through surgery or who experience high pain levels. Massage can also help people sleep better, though it may be contraindicated in patients with some forms of cancer or who are taking certain medications. It can be used alongside CBT, mindfulness, or yoga to promote sleep in patients who enjoy it and find it helpful.

Practicing Proper Sleep Hygiene

In addition to the techniques above, cancer patients and anyone who struggles to sleep should practice good sleep hygiene. This includes the following steps:

  • Creating a sleep routine. Set firm times to go to sleep and wake up. Do the same things, in the same order, before bed every night.
  • Avoid blue light. This light prevents the brain from producing melatonin, which it needs in order to rest.
  • Avoid caffeine in the afternoon.
  • Limit daytime naps. This helps ensure that the patient is sleepy when it’s time to rest at night.
  • Get at least 10 minutes of exercise. This can be extremely difficult for cancer patients but should be part of their routine if at all possible, because it makes a big difference in sleep.
  • Avoid food that causes sleep disruption. If the patient knows that something affects how they sleep or how well they sleep, they shouldn’t eat it before bedtime.
  • Only use the bedroom for sleep and sex. This will help train the brain that the bedroom is a place for sleep and nothing more.

Creating a Comfortable Sleep Environment

An important part of practicing good sleep hygiene is creating an environment that is conducive to sleep. Make sure the room is a comfortable temperature and that the sleeper has blankets available if they get cold. Do your best to eliminate extra noise: turn off the television, close the doors and windows, and ask people to be quiet. If necessary, invest in a quality pair of earplugs to further block noise.

You should also turn the lights off or wear an eye mask, remove disruptive pets or children from the bedroom, and make sure you have a comfortable mattress. A patient is more likely to sleep well when he or she feels restful in the bedroom.

Light Therapy

Light therapy is another common way to treat insomnia. Most doctors don’t use this unless other things have not worked, so it’s worth asking about if your insomnia is persistent and intractable. This therapy involves sitting next to a full-spectrum light box for a particular amount of time each day. The light helps reset your circadian rhythms, which can help your body know when to sleep.

The therapy can be difficult for cancer patients, though, because it works best when the person can sit in front of the light for the same amount of time, starting at the same time, every single day. Since cancer patients have treatments and often don’t know how their energy levels will be, it can be hard to commit to the treatment.

Insomnia is not a life sentence. Whether a person has cancer, wants to prevent it, or simply wants to sleep through the night, the techniques above can help them do that. No one should feel like sleeping well is hopeless. Doctors, psychologists, and other professionals can help insomniacs regain control of their sleep so that they can feel rested and get through their days easily.

Additional Resources

The American Cancer Society Resource Search – Find resources to deal with your cancer and related issues. Enter your location to get connected to resources near you.

The Association of Cancer Online Resources – Get accurate information quickly over the internet. Join one of ACOR’s 142 communities to get access to the people and data you need to make informed decisions about your treatment.

Breastcancer.org Community – Connect with patients who have or have had the same diagnosis that you have. Learn about cutting-edge therapies and other treatment options.

Cancer.net – Find out information about treatment options, oncologists, and treatment locations.

CancerCare – Connect with support groups, therapists, financial aid and more.

Cancer Support Community – Get your own, personalized website where you can communicate updates on your status and treatment to friends and relatives. Connect with people who have your same diagnosis for support and information.
National Coalition for Cancer Survivors – Learn about changes in the law that may affect your cancer treatment, and connect to sites for specific types of cancer.

Studies Cited in Our Report

Sleep Disruption Among Older Men and Risk of Prostate Cancer – Older men who struggled to stay asleep or who did not sleep enough had a greater risk of developing prostate cancer, especially advanced prostate cancer.

Short Duration of Sleep Increases Risk of Colorectal Adenoma – People who slept less than 6 hours per night were almost 50% more likely to develop colorectal cancer when compared to others who slept at least 7 hours per night.

Association of Sleep Duration and Breast Cancer OncotypeDX Recurrence Score – Women who regularly did not sleep as much were more likely to develop aggressive breast cancer tumors.

Night Shift Work, Chronotype and Prostate Cancer Risk in the MCC-Spain Case-control Study – Long-term night shift workers demonstrated a higher risk of prostate cancer, and of developing more aggressive tumors.

Nested Case–control Study of Night Shift Work and Breast Cancer Risk Among Women in the Danish Military – Women who worked many long night shifts had a greater chance of developing breast cancer.  

Association of Shift-work, Daytime Napping, and Nighttime Sleep with Cancer Incidence and Cancer-caused Mortality in Dongfeng-tongji Cohort Study – Men who worked the night shift for many years and did not nap, as well as men who slept more than 10 hours per night, were at a greater risk for cancer.

Melatonin Decreases Estrogen Receptor Binding to Estrogen Response Elements Sites on the OCT4 Gene in Human Breast Cancer Stem Cells – Treating certain cancer cells with melatonin inhibited their growth.

Insomnia and Cancer: Prevalence, Nature, and Nonpharmacologic Treatment – Insomnia is extremely common in cancer patients but can be treated.

Fatigue, Depression, and Insomnia: Evidence for a Symptom Cluster in Cancer – Fatigue, depression, and insomnia seem to come together for cancer patients, so treating one condition may help in treating the others, too.

The Development and Impact of Insomnia on Cancer Survivors: A Qualitative Analysis – Insomnia often starts at diagnosis, gets worse during active treatment, and remains after treatment is completed, lowering quality of life until it is treated.

Symptom Distress in Newly Diagnosed Ambulatory Cancer Patients and as a Predictor of Survival in Lung Cancer – Stress over cancer symptoms ties to insomnia, certain people are more likely to be stressed about their cancer than others, and higher stress leads to lower survival rates.

Randomized Study on the Efficacy of Cognitive-Behavioral Therapy for Insomnia Secondary to Breast Cancer, Part I: Sleep and Psychological Effects – Cognitive Behavioral Therapy helps cancer patients sleep better and improves their quality of life, with long-lasting effects.

The Efficacy of Mindfulness-Based Stress Reduction in the Treatment of Sleep Disturbance in Women with Breast Cancer: An Exploratory Study – CBT improves sleep in women with breast cancer whose insomnia is due to stress.

Yoga as Treatment for Insomnia Among Cancer Patients and Survivors: A Systematic Review – Yoga has potential as a treatment for cancer patients and survivors who suffer from high levels of stress that result in insomnia.