Longitudinal development of fatigue after treatment for childhood cancer: a national cohort study.

Background: Fatigue is a distressing and prevalent long-term sequela of treatment for childhood cancer, and there is a need for longitudinal studies to investigate the development of fatigue over time. The objective of this study was to calculate growth-curves for the longitudinal development of fatigue after treatment for childhood cancer, and to investigate the effects of biopsychosocial predictors.

Materials And Methods: Participants were recruited from a patient monitoring program and data extracted from medical records. Parent-proxy and self-report versions of PedsQL Multidimensional Fatigue Scale were used to repeatedly assess fatigue up to 5 years after the end of treatment for childhood cancer. Fatigue was assessed 2440 times for 761 participants (median:3) with proxy-reports (age 2-8 years) and 2657 times for 990 participants with self-reports (above 8 years) (median:2). Mixed models were used to establish growth-curves and to analyze the effect of predictors separately for participants with solid tumors (ST), hemato-oncological malignancies and central nervous system-tumors (CNS).

Results: CNS-tumors were associated with more cognitive fatigue than ST at the end of treatment, for both proxy-reports (-11.30, <.001) and self-reports (-6.78, =.002), and for proxy-reports of general fatigue (-6.78, =.002). The only significant difference in change over time was for self-reports of sleep-rest fatigue. The raw scores for the CNS-group decreased with -0.87 per year (95% CI -1.64; -0.81, =.031) compared to the ST-group. Parental distress was overall the variable most associated with increased fatigue, while immunotherapy was the most frequent medical predictor. National centralization of childhood cancer care decreased fatigue for the CNS-group, but not for other diagnoses.

Discussion: Children and adolescents treated for CNS-tumors reported more fatigue than other participants after the end of treatment, and this difference remained over time. Results from this study may help to facilitate the early recognition of children with insufficient recovery of fatigue symptoms.