Introduction: Daytime fatigue and poor quality sleep are more common in patients treated for cancer than healthy populations. Self-reported sleep disturbance is significantly associated with fatigue severity in post-cancer fatigue (PCF) [1]. Indeed a recent review suggested that sleep disturbance may be underreported by patients. In women treated for breast cancer early menopause-associated vasomotor symptoms may trigger sleep disturbance. A "domino theory" of sleep disruption leading to insomnia followed by fatigue and depression has been suggested, whereby, despite alleviation of the vasomotor symptoms insomnia may persist, driving ongoing fatigue. An alternative hypothesis is that PCF and cancer-related sleep disorders may share a common underlying aetiology.
Methods: Women treated for early-stage breast cancer participated in a prospective cohort study exploring the aetiology of PCF. Clinical assessment and blood sampling were performed post-surgery (baseline) and repeated at end-adjuvant treatment and 1, 3, and 6 months later. Physical and psychological health was monitored using interviews and self-report questionnaires.
Results: Data from 218 women (median age 52) were evaluated. The case-rate for PCF was 24% post-surgery, 42% at end-treatment, and 19% at 6-months. “Poor sleep” was reported by 71% of cases with cancer related fatigue at end-treatment and 70% at six months, compared to 33% and 25% of subjects without fatigue. Women who were pre-menopausal at baseline (n=104) were not more likely to be fatigue cases at 6 months post-treatment (X2 .01; p=.92). The only significant predictor of PCF was ‘sleep disturbance’ at 1-month post-treatment (odds ratio, 1.2; 95% confidence interval, 1.0-1.4; p=.047).
Conclusions: Sleep disturbance was prevalent in patients with fatigue. However, menopausal status was unrelated to sleep disturbance. Sleep disturbance at one-month post-treatment predicted PCF. Sleep disturbance is a likely contributor to the genesis of PCF suggesting that targeted, early intervention for sleep disturbance may be warranted in patients treated for cancer.
Roscoe, J A et al. Cancer-related fatigue and sleep disorders The Oncologist 2007;12(suppl 1):35–42