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Breast Cancer Patients have Progressively Impaired Sleep-Wake Activity Rhythms during Chemotherapy

2009; Oxford University Press; Volume: 32; Issue: 9 Linguagem: Inglês

10.1093/sleep/32.9.1155

1550-9109

Josée Savard, Lianqi Liu, Loki Natarajan, Michelle Rissling, Ariel B. Neikrug, Feng He, Joel E. Dimsdale, Paul J. Mills, Barbara A. Parker, Georgia Robins Sadler, Sonia Ancoli‐Israel,

Sleep and related disorders

REPORT insomnia symptoms. 1,2 There is also evidence suggesting that breast cancer patients constitute the subgroup of cancer patients most at risk for experiencing sleep difficulties. 3,4 In addition to resulting in restless sleep (i.e., increased activity during the night), breast cancer and its treatment may also reduce daytime activity.Although data are rather sparse, there is some evidence to suggest that cancer patients have disturbed circadian rhythms.6][7][8][9] But few have examined circadian variables before and during treatment in cancer patients.Some data on breast cancer patients suggest that sleep and circadian rhythms may be altered even prior to the initiation of chemotherapy. 10,11These studies found that breast cancer patients slept for about 6 hours, spent about a quarter of the night awake and napped for a total of about one hour a day.While their circadian rhythms were not desynchronized, those with more phase-delayed rhythms experienced more daily dysfunction.Together, these studies are consistent in showing some alterations in the rest-activity circadian rhythms of cancer patients.However, as no longitudinal study has been published, it is unknown to what extent these impairments evolve over time.As part of a larger study on sleep, fatigue, rhythms and breast cancer, the goal of this study was to assess the evolution of circadian impairments longitudinally, i.e., before and during chemotherapy for breast cancer. METHODS ParticipantsThe majority of patients were referred by oncologists from the Rebecca and John Moores University of California San Diego (UCSD) Cancer Center.Patients were also referred from community oncologists in the San Diego, CA, and the Yakima, WA, areas.Patients were eligible for the study if they had recently received a diagnosis of stage I-III breast cancer and were scheduled to receive ≥ 4 cycles of neoadjuvant or adjuvant anthracyclinebased chemotherapy as part of their cancer treatment.The study excluded women who were shift workers, pregnant, had metastatic or IIIB (including inflammatory) breast cancer, had significant pre-existing anemia, had received radiation therapy prior to their chemotherapy, were undergoing bone marrow transplant, and those with confounding comorbid medical illnesses or any other physiological or psychological impairments (e.g., major depression) that would have limited their participation.