Sleep quality linked to cognitive decline in older breast cancer survivors

By Will Pass


For some older breast cancer survivors, getting a good night’s sleep could be essential to maintaining a healthy brain, according to a recent study.

One-third of breast cancer survivors 60 years and older reported trouble sleeping, and in patients with particular genes, nights of tossing and turning negatively affected learning and memory, reported lead author Judith E. Carroll, PhD, of the University of California, Los Angeles, and colleagues. These findings point to how sleep disturbance, individual genetics, and declining brain function over time among cancer survivors might be connected, the investigators explained.

“Sleep disturbance has been identified as a risk factor for the development of cognitive decline and Alzheimer disease (AD) in noncancer populations,” the investigators wrote in Cancer. “Likewise, a number of genetic vulnerabilities for cognitive decline in later life … have been identified.”

Despite this knowledge, few studies have explored these risks among cancer survivors even though cancer survivors often have trouble sleeping.
For cancer survivors, the consequences of not treating sleeping problems may be far reaching.
“The contribution of sleep to cognitive declines and genetic vulnerability among cancer survivors remains relatively unexplored despite the observation that sleep disturbance is highly prevalent among cancer survivors, with the incidence of insomnia in cancer survivors 2- to 3-fold greater than rates among similarly aged controls,” the investigators wrote.

To see how sleep and genes might be contributing to cognitive decline in cancer survivors, the investigators recruited 319 women with breast cancer who were 60 years or older. All participants were tested for genes associated with cognitive decline. In addition, questionnaires and assessments of cognitive function were performed at three timepoints: before systemic therapy, 1 year later, and 2 years later. Over time and between patients, the investigators compared patient genes with changes in sleep quality and cognitive function, looking for links among the factors.

 
For cancer survivors, the consequences of not treating sleeping problems may be far reaching.

“A failure to assess and treat [cancer survivors] for sleep disturbance could potentially have a long-term impact on their risk for later cognitive difficulties,” the investigators wrote. “Sleep also has a significant impact on other important patient outcomes, including mood, fatigue, quality of life, risk for secondary cancers, cardiovascular disease, metabolic syndrome, diabetes, and biological aging.”

Considering all of the above consequences, the investigators suggested that health care professionals and patients keep sleep quality in mind.

“Although the findings in the current study are preliminary, the results support screening for and addressing patient complaints about sleep disturbance as a typical clinical and preventative behavioral health target similar to diet, exercise, and smoking.”

If sleeping problems are detected, Dr. Carroll and colleagues encouraged appropriate treatment, noting that some options are better than others.

“Common behavioral treatments have established efficacy in cancer patient populations,” they wrote, also noting that sleep medications may not be so reliable. In the present study, patients who took sleep medications did not, on average, report better sleep than did those who refrained from taking similar medications.

In regard to the future, the investigators suggested that more work is needed to gain a clearer picture of the relationships among genes, sleep, and cognitive decline in cancer survivors. Specifically, they suggested that future studies measure sleep quality directly and over a longer period of time.

The study was funded by the National Cancer Institute and the American Cancer Society. The investigators reported additional relationships with Amgen, Seattle Genetics, AstraZeneca, and others.

For cancer survivors, the consequences of not treating sleeping problems may be far reaching.

“A failure to assess and treat [cancer survivors] for sleep disturbance could potentially have a long-term impact on their risk for later cognitive difficulties,” the investigators wrote. “Sleep also has a significant impact on other important patient outcomes, including mood, fatigue, quality of life, risk for secondary cancers, cardiovascular disease, metabolic syndrome, diabetes, and biological aging.”

Considering all of the above consequences, the investigators suggested that health care professionals and patients keep sleep quality in mind.

“Although the findings in the current study are preliminary, the results support screening for and addressing patient complaints about sleep disturbance as a typical clinical and preventative behavioral health target similar to diet, exercise, and smoking.”

If sleeping problems are detected, Dr. Carroll and colleagues encouraged appropriate treatment, noting that some options are better than others.

“Common behavioral treatments have established efficacy in cancer patient populations,” they wrote, also noting that sleep medications may not be so reliable. In the present study, patients who took sleep medications did not, on average, report better sleep than did those who refrained from taking similar medications.

In regard to the future, the investigators suggested that more work is needed to gain a clearer picture of the relationships among genes, sleep, and cognitive decline in cancer survivors. Specifically, they suggested that future studies measure sleep quality directly and over a longer period of time.

The study was funded by the National Cancer Institute and the American Cancer Society. The investigators reported additional relationships with Amgen, Seattle Genetics, AstraZeneca, and others.

 

Indeed, links were found. Overall, one-third of patients reported trouble sleeping at any timepoint. When patients who carried the APOE gene reported sleep disturbance, they were more likely than noncarriers to score progressively worse on learning and memory tests. Similarly, patients who tested positive for the COMT gene were more likely to self-report worse cognitive function after sleeping poorly than were patients without the COMT gene. These findings support previous research in the general population and, in turn, the importance of quality sleep, according to the investigators.

“Our findings extend the existing evidence that has linked sleep disturbance with cognitive decline and dementia risk in noncancer populations,” they wrote.

 

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