Insomnia Highly Prevalent in Cancer Patients

[RandyW]

June 13, 2008 (Baltimore, Maryland) — Cancer patients undergoing chemotherapy are nearly 3 times more likely to have insomnia than the general population, a new study shows.

"While this may initially be ascribable to the level of life stress that accompanies being diagnosed with cancer, the persistence of insomnia across treatment and into remission remains inordinately high," the researchers, led by Oxana G. Palesh, PhD, assistant professor in the psychiatry and behavioral medicine unit at the University of Rochester Medical Center, in New York, conclude.

Taken together with previous research that has shown that insomnia remains high during remission, they note, "these prevalence rates suggest that behavioral factors may be interacting with disease factors to produce greater insomnia morbidity."

Their findings were reported here at SLEEP 2008: 22nd Annual Meeting of the Associated Professional Sleep Societies.

Negative Effects

In the general population, insomnia has many negative effects, including influencing cardiac and immune functions. Although the full impact of sleep deprivation on cancer patients is unknown at this time, the consequences of insomnia are expected to be similar to or worse than those in the general population. Cancer patients with insomnia might have less response to treatment, and the effect on their immune system might have an impact on disease progression and overall survival.

The current study is a secondary analysis of 823 cancer patients who participated in the larger University of Rochester Cancer Center Community Clinical Oncology (URCC CCOP) study.

The mean age of the participants was 56.9 ± 12.6 years, 72.4% were women, and 88.7% were white. In terms of previous treatment, 68.8% of the patients had undergone surgery, 14.2% had undergone chemotherapy, and 11% had undergone radiation therapy, Dr. Palesh said. The most common cancer was breast cancer, present in 49.7% of patients. In 32% of the patients, the cancer was metastatic.

Dr. Palesh and colleagues monitored the prevalence of insomnia and depression in this patient population. Insomnia persisted through chemotherapy and was not reduced by antidepressant therapy, Dr. Palesh told Medscape Psychiatry.

In her presentation, Dr. Palesh reported that 76% of cancer patients had insomnia at the beginning of the first cycle of chemotherapy. The majority of patients continued to have insomnia throughout the treatment: 59% reported insomnia symptoms during and after cycle 2 of chemotherapy, and 45% of patients reported still having insomnia during cycle 4.

They also found significant differences by cancer diagnosis. "Interestingly, in this patient population, lung cancer patients have the highest prevalence of insomnia," said Dr. Palesh. Colon cancer patients reported the least insomnia, possibly because of chemotherapy regimens that result in fewer adverse events, speculated Dr. Palesh.

"Surprisingly, there was no difference in insomnia between men and women, contrary to what is seen in the general population," noted Dr. Palesh. Also, younger cancer patients had more insomnia, a trend opposite to that in the general population, possibly due to the amount of daily stress and demands on their time that come from work or taking care of children while undergoing chemotherapy, she explained.

Patients diagnosed with insomnia exhibited significantly more mood disturbances, depression, and fatigue than those who did not meet the diagnostic criteria for insomnia (P < .001 for all comparisons), the investigators noted.

Looking at depression in this patient population, Dr. Palesh indicated that 26.4% of patients met the criteria for depression, assessed using the Center for Epidemiologic Studies Depression Scale (CES-D ≥ 19) at cycle 1. "Those patients with clinical insomnia had more depression," she said. "Antidepressants, such as paroxetine, had no impact on insomnia symptoms," she noted.

Factors Other Than Cancer and Treatment?

"Insomnia patients, during cancer treatment, do not necessarily remit just as a function of the cancer being treated," Jack D. Edinger, PhD, clinical professor in the department of psychiatry, division of medical psychology at Duke University Medical Center and senior psychologist for the VA Medical Center, in Durham, North Carolina, said in an interview with Medscape Psychiatry.

Dr. Edinger, who chaired the session, stressed that "insomnia has a certain persistence, which may imply that there are other factors, in addition to the cancer or the adjustment to the cancer, that are perpetuating the disease, and those are the factors that most likely need attention and treatment focus."

"The study is asking whether, if you start treating the cancer, insomnia goes away," added Dr. Edinger. "Insomnia is the most common residual symptom of depression, yet treating depression doesn't necessarily take care of the insomnia. Likewise, we shouldn't expect it in other diseases, including serious medical disease," he concluded.

The study was supported in part by grants from the National Institutes of Health. Drs. Palesh and Edinger have disclosed no relevant financial relationships.

SLEEP 2008: 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS). Abstract 0698. Presented June 10, 2008.

Pearls for Practice

The prevalence of insomnia is higher during treatment and remission in patients with cancer compared with the general population, with a rate of 76% in cycle 1, 59% in cycle 2, and 45% in cycle 4 of chemotherapy.

In cancer patients, insomnia has the highest prevalence among lung compared with colon cancer patients; younger patients are more susceptible; there is no sex difference in prevalence; and insomnia is associated with greater depression and fatigue.

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