By Jill Delsigne
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| Continuous positive airway pressure machines help patients with sleep apnea breathe. Mask sizes and shapes vary and may cover the patient’s nose only or the nose and mouth. Cancer patients, especially those who have had maxillofacial surgery, may have difficulty finding the mask and system that work best for them. |
Estimates of the percentage of cancer patients affected by sleep disorders range from 30% to 88%. Sleep apnea is more common among cancer patients than in the general population, and cancer patients are twice as likely as people without cancer to experience insomnia.
The restless nights caused by sleep disorders can impair patients’ quality of life, immune systems, cognitive abilities, and abilities to function day to day. “Patients often say they feel like different people when they lose sleep; they struggle with poor concentration and memory,” said Dave Balachandran, M.D., an associate professor in the Department of Pulmonary Medicine at The University of Texas MD Anderson Cancer Center. “Daytime sleepiness affects their ability to function, affecting every aspect of their lives.” These effects can last far beyond treatment, becoming a chronic condition. Some breast cancer survivors, for example, have had sleep disorders up to 10 years after finishing treatment.
Despite the pervasiveness of sleep disorders in cancer patients, not much research is available on the relationship between cancer and sleep. MD Anderson researchers are leading the development of this field with the world’s first sleep center dedicated to cancer patients. At the sleep center, Dr. Balachandran and his colleagues are exploring the relationship between cancer and sleep, particularly whether conditions such as insomnia and sleep apnea are contributing factors to cancer development, symptoms of disease, or side effects of treatment. The researchers also are developing sleep disorder treatments tailored to cancer patients.
Sleep apnea
Sleep apnea has recently been shown to have a strong correlation with death from cancer. This is not surprising when one considers the prevalence of sleep apnea among cancer patients. Research done by Carmen Escalante, M.D., chair of the Department of General Internal Medicine, and Ellen Manzullo, M.D., a professor in the department, found that almost 30% of patients reporting cancer-related fatigue were diagnosed with sleep apnea.
Sleep apnea can result from several types of cancer treatment. Up to 80% of patients with head and neck cancer suffer from sleep apnea as a comorbidity or as a result of surgery or radiation therapy, according to the research of Saadia Faiz, M.D., an assistant professor in the Department of Pulmonary Medicine. Patients with breast cancer are particularly vulnerable to sleep apnea related to weight gain, which is a common side effect of breast cancer treatment. Narcotics and sleep medications given to relieve symptoms of any type of cancer also can contribute to sleep apnea.
Sleep apnea may accelerate cancer progression or interfere with cancer treatment. In vitro and animal studies have shown that intermittent hypoxia, mimicking the effects of the recurrent airway obstruction characteristic of sleep apnea, causes cancer cells to be more likely to proliferate.
Because sleep apnea is common in cancer patients, patients who report excessive sleepiness should be evaluated by a sleep specialist. If sleep apnea is a possible culprit, the patient may need to undergo polysomnography, an overnight test that monitors breathing, sleep stages, rapid eye movement, and other sleep metrics.
The standard treatment for sleep apnea is the continuous positive airway pressure (CPAP) machine. The CPAP technicians at MD Anderson’s sleep center specialize in helping cancer patients find the mask and system that work best for them. Patients with head and neck cancer, for example, may need an adjusted mask if the standard air pressure will interfere with a surgery site. Other strategies are employed to make CPAP tolerable for patients with dry mouth as a result of chemotherapy or radiation therapy. Tailoring CPAP therapy to patient-specific needs has enabled CPAP patients at the sleep center to consistently use their masks and sleep through the night, at a compliance rate well above the 50% compliance rate in the general population.
Insomnia
Insomnia, the most prevalent sleep disorder in the general population, also affects up to 80% of cancer patients. According to an MD Anderson study, 60% of patients who reported cancer-related fatigue were diagnosed with insomnia. Clinically, insomnia is diagnosed by the following criteria: taking more than 30 minutes to fall asleep or waking for more than 30 minutes during the night, having difficulty conducting daytime functions, and experiencing these disturbances at least 3 nights per week.
The psychological stress of a cancer diagnosis can cause patients to lose sleep, as can schedule changes brought about by treatment. Patients requiring drug or radiation treatments at odd hours, for example, may find it extremely difficult to maintain a consistent sleep schedule.
The pain and other symptoms of the cancer itself and side effects of treatment—such as nausea, incontinence, or hot flashes—can also prevent patients from sleeping. In addition, medications to relieve other symptoms or to treat cancer can cause insomnia as a direct side effect. Inflammation, often the result of various types of treatment and of the cancer itself, also has been shown to affect the ability to sleep.
Radiation therapy, especially to the brain, can interfere with patients’ circadian rhythms and REM sleep cycles, inhibiting the signals for wakefulness and sleepiness. These signals are regulated by environmental cues known as zeitgebers. Zeitgebers include light, a regular meal schedule, social interactions, and daytime activity.
Treatments such as light therapy and stimulant therapy can help regulate circadian rhythms and establish a regular sleep-wake schedule for patients with insomnia. Sleep medications are often given to treat insomnia in cancer patients, especially those with advanced disease who are near the end of life. However, sometimes sleep medications are contraindicated because of potential adverse drug interactions. And, according to Dr. Balachandran, sleep medication is at best a short-term solution. When possible, he prefers to help patients develop healthy sleep behaviors that will benefit them in the long term.
Cognitive behavioral therapy, considered the standard of care for insomnia in the general population, has also shown great promise for cancer patients. Cognitive behavioral therapy has been shown to help 70%–80% of patients in the general population who receive it and to reduce by half the need for sleep medications taken by cancer patients.
Cognitive behavioral therapy has multiple components—stimulus control, sleep hygiene, relaxation, and others—that can be tailored to a patient’s needs. People with insomnia often respond well to stimulus control therapy, which reconditions them to associate their bedrooms only with sleep. As patients learn healthy sleep hygiene (for instance, developing a relaxing bedtime ritual; getting up if sleep is difficult and only returning to bed when sleepy; and controlling environmental factors such as light, temperature, and noise), sleep comes to them more easily. Progressive muscle relaxation and guided imagery are often also very effective.
Depending on the severity of the insomnia, patients can work individually with a psychologist or sleep specialist, participate in group therapy administered by a trained nurse or counselor, or self-administer cognitive behavioral therapy.
Self-administered cognitive behavioral programs geared toward a general population are currently available online and on CD, and researchers are working on developing a tablet application for cancer patients that will guide them through self-administered cognitive behavioral therapy. “This application will take into account the unique issues and challenges that cancer patients face,” Dr. Balachandran said, “and the platform will make this type of therapy widely accessible.”
Helping patients find help
Because quality sleep is essential to health and to recovery, several researchers have suggested that doctors ask cancer patients about sleep and fatigue at each medical visit and include sleep evaluation as part of the long-term follow-up. Patients often do not self-report these symptoms. In many cases, cancer patients with insomnia can benefit from referral to a psychologist or a sleep specialist.
For more information, contact Dr. Dave Balachandran at 713-563-4259.
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