STUDY OBJECTIVES: To compare sleep-wake rhythms, melatonin, and cancer-related fatigue in pediatric patients with acute lymphoblastic leukemia (ALL) to healthy children and to assess the association between sleep-wake outcomes and cancer-related fatigue. METHODS: A national cohort of ALL patients (2-18 years) was included. Sleep-wake rhythms were measured using actigraphy and generated the following variables: Interdaily stability (IS): higher IS reflects higher stability; intradaily variability (IV): lower IV indicates less fragmentation; L5 and M10 counts: activity counts during the five least and 10 most active hours, respectively; and relative amplitude (RA): the ratio of L5 and M10 counts (higher RA reflects a more robust rhythm). The melatonin metabolite, 6-sulfatoxymelatonin (aMT6s), was assessed in urine. Cancer-related fatigue was assessed with the PedsQL Multidimensional Fatigue Scale. Using regression models sleep-wake rhythms, aMT6s, and cancer-related fatigue were compared to healthy children and associations between sleep-wake outcomes and cancer-related fatigue were assessed in ALL patients. RESULTS: In total, 126 patients participated (response rate: 67%). IS, RA, and M10 counts were lower in patients compared to healthy children (p < 0.001). aMT6s levels were comparable to healthy children (p = 0.425). Patients with ALL were more fatigued compared to healthy children (p < 0.001). Lower IS, RA and M10 counts and higher IV were significantly associated with more parent-reported cancer-related fatigue. Associations between sleep-wake rhythms and self-reported cancer-related fatigue were not statistically significant. CONCLUSIONS: Sleep-wake rhythm impairment is associated with more cancer-related fatigue in pediatric ALL patients. Interventions aimed to improve sleep hygiene and encourage physical activity may reduce cancer-related fatigue.

actigraphy, acute lymphoblastic leukemia, cancer-related fatigue, children sleep–wake rhythms, physical activity,

Steur, L.M.H. (Lindsay M H), Kaspers, G.J.L, van Someren, E.J.W, Van Eijkelenburg, N.K.A. (Natasha K A), van der Sluis, I.M, Dors, N, … van Litsenburg, R.R. (2020). Sleep-wake rhythm disruption is associated with cancer-related fatigue in pediatric acute lymphoblastic leukemia. Sleep, 43(6). doi:10.1093/sleep/zsz320