Disordered sleep has been found to be common in cancer survivors and contributes to fatigue and impaired overall functioning. The true prevalence and incidence of sleep disorders in the oncology population is not well documented, though reports range from 23%–61%. Some research suggests that sleep-wake disturbances are more prevalent in patients with cancer than in other populations. In addition, Miller and colleagues, suggest that a disturbed sleep-wake cycle may well be a main predictor and contributor of other symptoms such as fatigue, depressed mood and cognitive dysfunction. Evaluating and improving sleep may have broad ramifications for cancer survivors.
Insomnia is present when there is repeated difficulty initiating or maintaining sleep or impairment in sleep quality that occurs despite adequate time and opportunity for sleep, and there is some form of daytime impairment as a result. Secondary insomnia is denoted when insomnia is prominent and develops in the setting of another primary medical or psychiatric illness, or in the setting of a separate sleep disorder such as sleep apnea. Sleep disturbance can be associated with poor work performance, increased anxiety and depression, poor cognitive functioning, and impairment of overall QOL. A recent Institute of Medicine report highlighted the severe costs to individual and society of untreated insomnia.