Actigraphy-measured sleep disruption as a predictor of survival among women with advanced breast cancer.
BACKGROUND
Poor sleep, prevalent among cancer survivors, is associated with disrupted hormonal circadian rhythms and poor quality of life. Using a prospective research design, this study aimed to clarify the relationship between objective measures of sleep efficiency and sleep disruption with survival among women with advanced breast cancer.


METHODS
We examined sleep quality and duration via wrist-worn actigraphy and sleep diaries for 3 days among 97 women in whom advanced breast cancer was diagnosed (age = 54.6 ± 9.8 years). Sleep efficiency was operationalized using actigraphy as the ratio of total sleep time to total sleep time plus wake after sleep onset.


RESULTS
As hypothesized, better sleep efficiency was found to predict a significant reduction in overall mortality (hazard ratio [HR], 0.96; 95% confidence interval [CI], 0.94-0.98; P < 0.001) at median 6 y follow-up. This relationship remained significant (HR, 0.94; 95% CI, 0.91-0.97; P < 0.001) even after adjusting for other known prognostic factors (age, estrogen receptor status, cancer treatment, metastatic spread, cortisol levels, and depression). Secondary hypotheses were also supported (after adjusting for baseline prognostic factors) showing that less wake after sleep onset (HR, 0.41; 95% CI, 0.25-0.67; P < 0.001), fewer wake episodes, (HR, 0.93; 95% CI, 0.88-0.98; P = 0.007); and shorter wake episode duration (HR, 0.29; 95% CI, 0.14-0.58; P < 0.001) also contributed to reductions in overall mortality.


CONCLUSIONS
These findings show that better sleep efficiency and less sleep disruption are significant independent prognostic factors in women with advanced breast cancer. Further research is needed to determine whether treating sleep disruption with cognitive behavioral and/or pharmacologic therapy could improve survival in women with advanced breast cancer.
Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA.
Oxana
O
Palesh
Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA.
Arianna
A
Aldridge-Gerry
Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA.
Jamie M
JM
Zeitzer
Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA.
Cheryl
C
Koopman
Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA.
Eric
E
Neri
Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA ; Tom Baker Cancer Centre, Psychosocial Resources, Calgary, Canada.
Janine
J
Giese-Davis
Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA.
Booil
B
Jo
Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA.
Helena
H
Kraemer
Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA.
Bita
B
Nouriani
Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA.
David
D
Spiegel
D056044:Actigraphy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000150:complications* / Q000401:mortality* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D057566:Self Report; D012890:Sleep / Q000502:physiology; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications* / Q000503:physiopathology*; D016019:Survival Analysis; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology
advanced breast cancer; sleep disruption; sleep efficacy; survival; wake after sleep onset