Relationship between circadian activity rhythms and fatigue in hospitalized children with CNS cancers receiving high-dose chemotherapy

Purpose Robust circadian rhythms are increasingly recognized as essential to good health. Adult cancer patients with dysregulated circadian activity rhythms (CAR) experience greater fatigue, lower responsiveness to chemotherapy, and shorter time to relapse. There is scant research describing circadian rhythms and associated outcomes in children with cancer. As part of a larger study examining whether a cognitive-behavioral intervention could preserve sleep in children and adolescents with central nervous system cancers hospitalized for high-dose chemotherapy (HDCT), this study aimed to compare CAR of these children to published values and to investigate the relationship between CAR and fatigue. Methods Participants aged 4-19 years wore an actigraph throughout their hospitalization (5 days). From activity counts recorded by actigraphy, six CAR variables were calculated: amplitude, 24-h autocorrelation (r24), dichotomy index (I < O), interdaily stability (IS), intradaily variability (IV), and acrophase. Parent-reported child fatigue and child/adolescent self-reported fatigue measures were collected daily. Results Thirty-three participants were included. Three CAR variables (amplitude, r24, and I < O) showed dysregulation compared to published values. Older age was significantly associated with later acrophase and greater dysregulation of all other CAR variables. Controlling for age, more dysregulated amplitude (p = 0.001), r24 (p = 0.003), IS (p = 0.017), and IV (p = 0.001) were associated with higher parent-reported fatigue; more dysregulated IV (p = 0.003) was associated with higher child-reported fatigue. Conclusions Participants demonstrated dysregulated CAR during hospitalization for HDCT. Greater dysregulation was associated with greater fatigue. Research on circadian dysregulation and its relationship to health-related outcomes in children with cancer, and interventions to support circadian rhythmicity, is urgently needed.