Figure 1.

Proposed model showing assumed relations between factors and CF in CCS. Figure shows assumed relations of study parameters that have previously been found to be associated with CF.¹⁰ Triggering factors are assumed to play a role at the onset of fatigue. Maintaining factors are assumed to perpetuate fatigue once triggered. Moderating factors are assumed to have an effect on the strength of fatigue symptoms in individuals. The following change has been made compared with the model presented in¹⁰: age at diagnosis is considered a triggering factor ensuring all treatment/diagnosis-related factors are categorized in one group of factors as we assume childhood cancer and its treatment to be a triggering factor for fatigue. Also, we believe age at diagnosis to play a part at the onset of fatigue, which is the definition of the assumed triggering factors, and not so much a moderating factor many years after diagnosis. Comorbidities are categorized following previously published main organ system categories.¹¹ CF, chronic fatigue; CSS, childhood cancer survivors.