Purpose: Cross-sectional data suggest that many individuals with breast cancer experience significant sleep disturbance across the continuum of care. Understanding the longitudinal trajectory of sleep disturbance may help identify factors associated with its onset, severity, or influence on health-related quality of life (HRQL). Study objectives were to observe sleep quality in breast cancer patients prior to, during, and after completion of adjuvant chemotherapy, evaluate its relationship with HRQL and explore correlates over time.
Methods: Participants were administered patient-reported outcome measures including the Pittsburgh Sleep Quality Index (PSQI) and the Functional Assessment of Cancer Therapy--General (FACT-G), which assesses HRQL. Data were collected prospectively 3-14 days prior to beginning chemotherapy, cycle 4 day 1 of chemotherapy, and 6 months following initiation of chemotherapy.
Results: Participants (n = 80) were primarily women (97.5 %) with stage II (69.0 %) breast cancer. Total FACT-G scores were negatively correlated with global PSQI scores at each time point (rho = -0.46, -0.41, -0.45; all p < 0.001). Poor sleep quality (PSQI ≥ 5) was prevalent at all time points (48.5-65.8 %); however, there were no significant changes within participants over time. Correlates with sleep quality varied across time points. Participants with poor sleep quality reported worse overall HRQL, fatigue, depression, and vasomotor/endocrine symptoms.
Conclusions: These findings suggest that early identification of sleep disturbance and ongoing assessment and treatment of contributing factors over the course of care may minimize symptom burden associated with chemotherapy and prevent chronic insomnia in survivorship.