Effects of sleep disturbance, cancer-related fatigue, and psychological distress on breast cancer patients' quality of life: a prospective longitudinal observational study

More attention has gone to researching the cancer-related fatigue (CRF)-sleep disturbance (SD)-psychological distress (PD) symptom cluster in breast cancer patients during the chemotherapy period, but the change trend and heterogeneous development track in the whole treatment stage remain unclear, and it is also unclear whether the appearance of and changes in one symptom cause changes in other symptoms and quality of life (QoL). This study, using breast cancer patients' data collected through a validated questionnaire, examined the relationships between SD, CRF, PD, and QoL using latent growth modeling analyses. CRF developmental trajectories showed an upward trend over five surveys (slope = 0.649, P < 0.001); PD showed a significant weakening trend (slope = - 0.583, P < 0.001); SD showed an increasing trend (slope = 0.345, P < 0.001), and QoL showed a statistically significant weakening trend (slope = - 0.373, P < 0.001). The initial CRF (coefficient = - 0.233, P < 0.01), PD (coefficient = - 0.296, P < 0.01), and SD (coefficient = - 0.388, P < 0.001) levels had a statistically significant negative effect on initial QoL level. The linear development rate of PD was statistically significant and negatively affected that of QoL (coefficient = - 0.305, P < 0.05), whereas the quadratic development rate of SD negatively affected that of QoL (coefficient = - 0.391, P < 0.05). Medical staff should identify the change characteristics of different variables based on SD, CRF, PD, and QoL change trajectories, and advance the intervention time, as changes in variables affect other variables' subsequent changes.