Sleep-wake circadian activity rhythm parameters and fatigue in oncology patients before the initiation of radiation therapy

Background: Little is known about the relationships between sleep parameters and fatigue in patients at the initiation of radiation therapy (RT). Objectives: The objectives of this study were to describe values for nocturnal sleep/rest, daytime wake/activity, and circadian activity rhythm parameters measured using actigraphy and to evaluate the relationships between these objective parameters and subjective ratings of sleep disturbance and fatigue severity, in a sample of patients at the initiation of RT. Methods: Patients (n = 185) with breast, prostate, lung, or brain cancer completed self-report measures for sleep disturbance (ie, Pittsburgh Sleep Quality Index, General Sleep Disturbance Scale) and fatigue (Lee Fatigue Scale) and wore wrist actigraphs for a total of 48 hours prior to beginning RT. Actigraphy data were analyzed using the Cole-Kripke algorithm. Spearman rank correlations were calculated between variables. Results: Approximately 30% to 50% of patients experienced sleep disturbance, depending on whether clinically significant cutoffs for the subjective or objective measures were used to calculate occurrence rates. In addition, these patients reported moderate levels of fatigue. Only a limited number of significant correlations were found between the subjective and objective measures of sleep disturbance. Significant positive correlations were found between the subjective, but not the objective measures of sleep disturbance and fatigue. Conclusions: A significant percentage of oncology patients experience significant disturbances in sleep-wake circadian activity rhythms at the initiation of RT. The disturbances occur in both sleep initiation and sleep maintenance. Implications for Practice: Patients need to be assessed at the initiation of RT for sleep disturbance, so appropriate treatment is initiated.