Sleep complaints are common in patients with cancer-related fatigue (CRF). However, sleep architectural changes associated with CRF and the contribution of primary sleep disorders have rarely been examined. At our Sleep Center and CRF Clinic, we investigated whether sleep disorders were a significant etiology of CRF.
We performed a retrospective study of patients evaluated in our CRF Clinic between 9/1/06 and 5/31/08. We identified all patients referred by the CRF clinic for a Sleep Center consult and reviewed their demographic, clinical, symptom status, and polysomnographic data.
Of 130 patients referred for a fatigue consult, 25% (n=32) were subsequently referred to the Sleep Center. The median age of these 32 patients was 55, 66% were female. Patient median BMI was 30.1 (ranging from 20.0–58.1). Most had good Zubrod performance scores (78%, n=25) and exhibited no evidence of disease (75%, n=24). Their median fatigue (BFI) was 6.2, while their median sleep disorder (BSDS) was 28.5. Sleep architecture varied from published norms in these patients with CRF. The mean total sleep time was 410 minutes, mean wake after sleep onset (WASO) was 67.5 minutes, and mean sleep latency and sleep efficiency were 14.6 and 85.32%, respectively. Mean percentages of stages of sleep were: W=14.3%, N1=14.0%, N2=58.6%, N3=3.8%, R=14.0%. Twenty of 22 patients studied polysmonographically were diagnosed with a primary sleep disorder: obstructive sleep apnea (n=16, 73%), periodic limb movement disorder (n=4, 18%). The mean apnea hypopnea index, periodic limb movement arousal index, and arousal index were 10.4 events/hour, 3.7 events/hour, and 28 arousals/hour, respectively.
Sleep architecture is fragmented in patients with cancer-related fatigue, exemplified by an increased arousal index, increased proportion of Stage N1 and N2 sleep, and decreased in stages N3 and R sleep.
Sleep disorders such as sleep apnea are common and under-recognized and should be considered in the differential diagnosis of CRF.
Diwakar Balachandran, No Financial Disclosure Information; No Product/Research Disclosure Information