The Relationship between Fatigue and Actigraphy-Derived Sleep and Rest-Activity Patterns in Cancer Survivors

Study Objectives: To investigate objectively-measured sleep and rest-activity cycles in fatigued and non-fatigued cancer survivors. We hypothesized that sleep and rest-activity cycles would be more disturbed in people experiencing clinically-relevant cancer-related fatigue, and that objective measures of sleep would be associated with the severity of fatigue in cancer survivors.
Methods: Cancer survivors (n = 87) completed a 14-day wrist actigraphy measurement for the objective assessment of sleep and rest-activity cycles. Fatigue was measured using the Functional Assessment of Chronic Illness Therapy-Fatigue Scale (FACIT-F). Participants were dichotomised into two groups using a previous validated cut off (fatigued n = 51 and non-fatigued n = 36). Perception of sleep was measured using the Insomnia Severity Index (ISI).
Results: FACIT-F score was correlated with wake after sleep onset (r = -0.28; p = 0.010), sleep efficiency (r = 0.26; p = 0.016), sleep onset latency (r = -0.26; p = 0.014) and ISI score (r = -0.56; p < 0.001). The relative amplitude of the rest-activity cycles was lower in the fatigued group vs. non-fatigued group (p = 0.017; d = 0.58).
Conclusions: After treatment for cancer, the severity of cancer-related fatigue is correlated with specific objective measures of sleep, and there is evidence of rest-activity cycle disruption in people experiencing clinically-relevant fatigue. Future studies should focus on the potential benefits of interventions that influence objective and subjective measures of sleep in people with chronic fatigue after cancer treatment.