The Dangers of Cancer-Related Insomnia

Insomnia affects 30 percent to 40 percent of people going through cancer treatment, and often persists long after treated has been completed. (In contrast, roughly 15 percent of the population cope with this symptom.) This symptom is more common in women, and the elderly, but can affect nearly anyone.


Importance and Dangers

Woman lying awake in bed


You may think of difficulty falling asleep when you think of insomnia, but insomnia includes other forms of sleep disruption as well, including awakening during the night, early awakening, and an inability to get enough sleep resulting in daytime tiredness. By definition, insomnia is usually present for 3 nights or more in a week and lasts for a period greater than one month.

Insomnia syndrome is defined as difficulty falling asleep lasting over 30 minutes, or nighttime awakenings that add up to over 30 minutes or both, with a ratio of time spent sleeping to time spent in bed less than 85 percent. To be called a syndrome there must also be evidence of impaired daytime functioning. Whether or not you meet these criteria, if insomnia is affecting your life, it's important to talk to your doctor.

Despite the common occurrence of insomnia in people with cancer, many patients do not bring this up, and many physicians fail to ask. Yet that doesn't mean it is a minor problem. Check out the following slides which describe how important insomnia is when it comes to the well-being of people with cancer.


Cancer Fatigue Related to Insomnia

Fatigued man rubbing his eyes

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Cancer fatigue is one the most annoying symptoms affecting people with cancer, and insomnia is an important cause.

In a study looking at lung cancer patients going through chemotherapy, insomnia was considered to be the 3rd leading cause of cancer fatigue. Insomnia ranked behind shortness of breath and cough, but before anxiety, nutrition status, and physical activity. Overall it was felt that insomnia had the greatest direct effect on fatigue of listed causes.

When we hear of tips for coping with cancer fatigue, exercise is usually high on the list. Perhaps insomnia should be addressed to a greater degree than it has among health professionals caring for cancer patients. Don't wait for your doctor to ask you about insomnia. If sleep disturbances are affecting your life, speak up.


Reduced Immune Function

Close-up of a tissue paper in a box

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Studies have found that insomnia alters immune and endocrine function, and has a powerful influence on the risk of infectious disease. Since cancer treatments such as chemotherapy may also predispose a person to infections, this can be double trouble.

It's long been known that insomnia affects the proper functioning of the immune system. Studies looking at vaccine response (that ability of the body to "learn" from exposure to a vaccination and mount a defense should it be exposed to that infectious disease) have found a poorer immune response in people who have been experiencing insomnia at the time of vaccination.

The Immune System Is Important in Cancer Treatment

Certainly, the risk of infection is important for cancer patients, but what has only recently been spoken of widely, is the effect of the immune system on ridding the body of cancer. The rapidly expanding field of immunotherapy, one which has been finding breakthroughs in even some hard-to-treat late-stage cancers, is based essentially on the theory that to best fight off a tumor, we need to restore and boost our body's own immune response to that tumor. Seen in this context, the proper care of insomnia may soon be considered an essential 'treatment" for cancer.


Poorer Function in Daily Life

man yawning in his car


For anyone who has ever been tired, the effect of a poor night's sleep involves more than a feeling of being tired. In fact, organizations such as the FAA and AMA have created safety rules based on the hazardous consequences of a lack of restful sleep.

Insomnia and Concentration and Memory

Insomnia can decrease concentration which can make the activities of daily living as well as occupational activities dangerous. Memory is also impacted significantly by insomnia, which can affect many areas of life.

The picture above is a reminder that all of us can suffer the consequences of insomnia, not just pilots, and surgical residents. Decreased concentration from insomnia can lead to further problems in our lives, which can lead to yet further problems. We've recently heard about the possible effect of a decreased memory due to lack of sleep on surgical residents. Yet what about the effect on people with cancer who are trying to learn the language of their disease? And add to that a little chemobrain as a side effect of chemotherapy? Thankfully, there is much that can be done to treat insomnia as will be discussed in the 3rd article in this series.


Reduced Adherence to Treatments

Chemotherapy drug bag
Harry Sieplinga/Getty Images

A problem that is common but not often addressed, is the impact of insomnia upon treatment adherence. Daytime sleepiness due to insomnia may lead to missed clinic appointments, chemotherapy visits, radiation therapy visits, and more, which can impact both the symptoms and outcome for people living with cancer.

At home, fatigue due to sleep disturbances can likewise be a concern with regard to cancer treatments. Many medications used for people with cancer, both anti-cancer therapies​ and medications to control the side effects of these therapies, are often taken on a precise time regimen. Missed doses, as well as doses taken in an irregular fashion, may lead to poor control of symptoms combined with a possible decrease in the efficacy of treatment.



Sad woman wearing a headscarf


Insomnia may lead to depression, a condition which is already common enough in cancer. By itself, roughly 15 percent to 25 percent of people with cancer fit the criteria for depression which goes beyond ordinary grief. In fact, depression is one of the surprising signs of insomnia that are hard to recognize and overlooked by many.


Lowered Survival

Breast Cancer Patient having Chemotherapy Treatment
Justin Paget / Getty Images

Sleep has been linked to cancer survival in several different ways, and across different cancers. Not only does sleep deprivation appear to raise cancer risk, but appears to lower survival in people with cancer as well.

Recent studies have found that sleep disruption is an independent predictor of survival in women with advanced breast cancer, and sleep duration, even before diagnosis, is a factor in survival.


Lower Quality of Life

sad woman


Insomnia can have a negative impact on quality of life for cancer patients, both during treatment and for an extended period of time after treatment has been completed.

Adding this to specific measures such as immune function, and lower survival and the treatment of insomnia and other sleep disturbances should rank high on the review of symptoms for people with cancer and during survivorship.


Elevates Cancer Risk

doctor sitting by patient's bed in a dark room

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In discussing the importance of insomnia it's important to note that people who have sleep problems or participate in shift work have a higher risk of developing cancer. In fact, shift work has been labeled a human carcinogen (cancer-causing agent.)

Therefore, not only is insomnia a serious condition in those who have cancer, it is something worth evaluating and treating, in nearly anyone. Given the importance of non-disrupted sleep discussed, make an appointment with your oncologist today if you feel that your nights are leaving you with less energy than they should.

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