mCancerPartner sat down recently with Deirdre Conroy, Ph.D., an associate professor of psychiatry and clinical director of the U-M Behavioral Sleep Medicine Program, to discuss the factors that determine a good night’s sleep, why it is especially important for cancer patients, and what treatment options are available.
mCancerPartner: Unless we have a nighttime job, most of us try to sleep at night and be awake in the daytime. How do circadian rhythms relate to sleep?
Dr. Conroy: Circadian rhythm is the name for your body’s internal clock. It is a 24-hour cycle that regulates many of your body’s functions, including appetite, body temperature, levels of energy, and the desire to sleep or wake up. Sleep is considered one of the body’s natural rhythms.
The most powerful signals to the biological clock are light and darkness. Darkness signals the brain to release melatonin, a naturally occurring hormone that helps regulate the sleep cycle. Bright light shuts down the production of melatonin and helps to signal the brain to awaken. When there is a mismatch between the timing of sleep and one’s internal circadian rhythm and the external environment (such as with shift work), this may have medical consequences like cardiovascular disorders, metabolic syndrome, even cancer. We have a number of tools for diagnosing sleep problems like these, including diaries, logs, questionnaires, and actigraphs (which are worn on the wrist and measure daily patterns of activity).
There are many factors that regulate sleep behaviors, such as the timing of our daily activities, but consistent signals to the biological clock help to regulate sleep.
mCancerPartner: Let’s talk about how sleep and circadian rhythms can become disrupted by cancer, leading to insomnia. How might this happen?
Dr. Conroy: Insomnia is a complex problem that typically evolves from three factors: predisposing, precipitating and perpetuating factors.
A predisposing factor may be that the person describes herself or himself as a worrier.
In this context, a diagnosis of cancer might precipitate a series of sleepless nights.
Then, if chemotherapy begins this may set up a number of perpetuating factors. The patient is already anxious and sleepless and the ongoing demands of chemotherapy may perpetuate a few poor nights of sleep into a full blown insomnia. A many as 60% of cancer patients report difficulty sleeping or staying asleep, though many (66%) say they experienced insomnia before their diagnosis and 58% say cancer aggravated their sleep problems. Studies also show that insomnia can persist well beyond the end of treatment.
Because sleep disorders can precipitate further adverse physical affects, it’s not surprising that cancer patients with insomnia also report increased pain, discomfort, fatigue and depression. Chemotherapy has also been shown to disrupt circadian rhythms: the longer the treatment, the more progressive the sleep disruption and related impairment, especially fatigue.
mCancerPartner: How is insomnia treated?
Dr. Conroy: Insomnia can be treated with prescription and non-prescription approaches. However, with cancer, we might want to be careful that we don’t make the patient’s fatigue level worse with the side effects of extra medications. There is a non-medicinal approach called cognitive behavior therapy for insomnia that can be considered by any cancer patient with insomnia. It’s an approach using three fronts:
• Behavior: identifying maladaptive behaviors surrounding sleep, such as irregular sleep/wake schedules, spending too much time in bed, etc.;
• Cognitive: becoming more aware of thoughts and expectations that might prolong episodes of insomnia;
• Education: learning about lifestyle changes that can contribute to better sleep.
Research suggests that improvements in sleep resulting from cognitive behavior therapy for insomnia are significant, durable, and should be considered as part of the treatment plan for cancer patients with insomnia. A recent study has combined the this approach with a stimulant medication during the day to avoid worsening next day fatigue; the study shows promising results after cancer treatment .
mCancerPartner: In closing, can you tell me about the field of research called chronotherapy, and how that might relate to cancer treatment?
Dr. Conroy: Chronotherapy is a field of research that aims at optimizing cancer treatments by integrating information about one’s circadian rhythms with the delivery of anticancer drugs. Based on an individual patient’s circadian “phase,” there may be optimal times during the day (or night) for administering cancer therapeutics. Studies suggest that possible outcomes from this form of personalized medicine might be milder nausea and fatigue, improved quality of life, perhaps even longer survival.
Take the next step:
• Learn more about insomnia and cognitive behavioral therapy for insomnia from the U-M Health System.
• Read about the three studies Dr. Conroy mentions:
- Savard, J., et al., Prevalence, clinical characteristics, and risk factors for insomnia in the context of breast cancer. Sleep, 2001. 24(5): p. 583-590.
- Roscoe, J., et al., Randomized Placebo-Controlled Trial of Cognitive Behavioral Therapy and Armodafinil for Insomnia After Cancer Treatment. J Clin Oncol, 2015. 33(2): p. 165-171.
- Innominato, P., et al., The circadian timing system in clinical oncology. Annals of Medicine, 2014. 46: p. 191-207.
The University of Michigan Comprehensive Cancer Center’s 1,000 doctors, nurses, care givers and researchers are united by one thought: to deliver the highest quality, compassionate care while working to conquer cancer through innovation and collaboration. The center is among the top-ranked national cancer programs, and #1 in Michigan according to U.S. News & World Report. Our multidisciplinary clinics offer one-stop access to teams of specialists for personalized treatment plans, part of the ideal patient care experience. Patients also benefit through access to promising new cancer therapies.