Characteristics and correlates of sleep disturbances in cancer patients.

PURPOSE: Few studies of sleep disturbances in cancer patients have focused on the period before chemotherapy starts. Understanding sleep disturbances in this period is important since early intervention has the potential to reduce the severity or chronicity of these problems. The present study sought to characterize sleep disturbances in this period, examine if they could be predicted by demographic, clinical, or lifestyle factors, and identify their relationship to fatigue, depression, and physical and mental well-being.
METHODS: Patients (N = 288) with breast cancer (32%), lung cancer (32%), or other cancers (36%) about to begin chemotherapy completed self-report measures assessing demographic and lifestyle characteristics, sleep, fatigue, depression, and quality of life.
RESULTS: Twenty-six percent of patients rated their sleep quality as fairly or very bad. Poorer overall sleep was significantly predicted by less education, more medical comorbidities, previous radiotherapy, less physical activity, and current tobacco use, but these variables accounted for only 7% of the variability in sleep disturbances. After controlling for significant relationships with depression and fatigue, sleep disturbances explained significant variability in physical well-being but not mental well-being.
CONCLUSIONS: Sleep disturbances are common before the start of chemotherapy and contribute to poorer physical well-being independent of fatigue and depression. Demographic, clinical, and lifestyle variables had limited value in predicting sleep disturbances. However, depression and fatigue were highly correlated with sleep. Future research should seek to identify common etiological factors (e.g., cytokine production) and implement longitudinal designs to examine temporal relationships among these three symptoms in cancer patients.