Time course and predictors of persistent cancer-related fatigue in long-term breast cancer survivors: a prospective observational study

Purpose: The present study investigated whether the level of cancer-related fatigue (CRF) after finishing oncology treatment was related to higher levels of persistent CRF and its relationship with both functional and psychological disturbances. Second, to identify potential predictors of persistent CRF. Methods: Eighty BC survivors were classified into non-fatigued (≤ 3.9) or fatigued (≥ 4), according to their Piper Fatigue Scale total score after finishing oncology treatment. The time course of fatigue and the impact on its domains, pain, mood state, perceived physical fitness, the level of physical activity, and quality of life were assessed at ≥ 5 years. Results: Women classified as fatigued after finishing oncology treatment had not only a higher prevalence of persistent CRF (41.2%) at the reassessment, but also greater levels of pain (P = .006 to .048) and mood disturbances (P = .007 to .015), and lower levels of physical fitness condition (P = .002 to .039) and quality of life (P < .001 to < .05) over time. Regression analyses revealed that "sadness/depression," "global health status," "physical activity level," and "type of treatment" were significant predictors of persistent CRF (r2 = .692). Conclusion: Higher levels of CRF implied greater levels of persistent CRF and a lower functional and psychological profile over time. 69.2% of of persistent CRF was explained. ; This work was supported by the Spanish Ministry of Economy and Competitiveness [Plan Estatal de I + D + I 2013–2016]; Fondo de Investigación Sanitaria del Instituto de Salud Carlos III [PI14/01627]; Fondos Estructurales de la Unión Europea (FEDER). This study took place thanks to the additional funding from the University of Granada, Plan Propio de Investigación 2016. Excellence actions: Units of Excellence; Scientific Excellence Unit on Exercise and Health (UCEES).