Sleep and quality of life in cancer patients

Current clinical practice and research in cancer patients has focused on supportive care needs as well as tumor control. Sleep disorders are commonly observed in cancer patients but they are under-reported by the patients, and infrequently elicited by their physicians. The prevalence of sleep disorders ranges from 30 to 60% in cancer patients and of insomnia from 18 to >50%. In the oncology population, insomnia often forms part of a symptom cluster consisting of pain, depression,anxiety, and most importantly fatigue. The pathophysiological basis of sleep disorders in cancer has not been fully elucidated but includes circadian rhythm disturbances and alterations in cortisol, melatonin, and cytokine secretion. Risk factors for sleep disorders can be categorized as predisposing, precipitating, and perpetuating factors, some of which are related to personal traits of the patients, and others which are related to the disease, its treatment, or reactions to it. Measurement of sleeprelated problems has varied from objective observation to a variety of sleep-specific questionnaires, to quality of life (QOL) instruments, the latter usually containing very few items regarding sleep. The most accepted and efficacious treatment for sleep difficulties in cancer patients is cognitive behavioral therapy. However, in some subgroups (e.g., palliative care patients) medications may be preferred. A combined pharmacological and behavioral approach may be necessary for some patients.Methodological problems are frequent in the literature on sleep and QOL in cancer patients. There is a need for consensus on definitions, instruments for measurement, and high-quality trials to assess the efficacy of therapies.