Preliminary effects of bright light on sleep in women with breast cancer

Abstract

9094 Background: Studies have shown that women with breast cancer undergoing chemotherapy report disturbed sleep. Studies have also suggested that these women have very little bright light exposure, yet it is known that bright light may improve sleep. We present preliminary data from an on-going study that addresses whether bright light improves sleep in women with breast cancer undergoing chemotherapy. Methods: 11 women (mean age=50.3 yrs, SD=8.4, range: 35–70 yrs) diagnosed with stage I-III breast cancer, scheduled to receive at least 4 cycles of adjuvant anthracycline-based chemotherapy participated. Sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI) and objective measures of sleep were assessed with 72-hours of actigraphy (Ambulatory Monitoring, Inc. and Respironics) at baseline (pre-chemotherapy) and during the last week of cycle 4 (C4). Participants were randomized into two treatment groups: bright white light (BWL; n=7) and dim red light (DRL; n=4). Both groups were instructed to self-administer light therapy for 30 minutes every morning throughout 4 cycles of chemotherapy. Results: In the BWL group, total sleep time (TST) increased by 41 min (SD=69), while wake time stayed approximately the same. In the DRL group TST decreased by 32 minutes (SD=30), while wake time increased by 27 minutes (SD=39). Subjectively, PSQI sleep latency subscale for BWL was reduced from 2.6 (SD=3.0, range=0–5) at baseline to 1.9 (SD=2.3, range=0–6) at C4, while for DRL, mean sleep latency increased from 2.7 (SD=2.5, range=0–5) at baseline to 3.0 (SD=3.0, range=0–6) at C4. PSQI total score for BWL decreased from 12.0 (SD=4.7, range=7–19) at baseline to 10.9 (SD=4.2, range=5–16) at C4 while for DRL it decreased from 8.3 (SD=3.1, range=5–11) at baseline to 7.7 (SD=5.1, range=2–12) at C4. Conclusions: Preliminary results suggest that bright white light may increase the number of hours of sleep in women undergoing chemotherapy, as well as decreasing sleep latency and improving sleep quality. As additional data are collected, we will be able to establish the significance of these effects. Supported by: CBCRP 11IB-0034, NCI CA112035, Litebook Company and the research service of the VASDHS. No significant financial relationships to disclose.