ABSTRACT & COMMENTARY
Precisely Timed Light May Reduce ChemotherapyRelated Sleep Disruption and Fatigue Results from a controlled pilot study REFERENCE
Wu H-S, Davis JE, Chen L. Bright light shows promise in improving sleep, depression, and quality of life in women with breast cancer during chemotherapy: findings of a pilot study. Chronobiol Int. 2021;38(5):694-704. STUDY OBJECTIVE
To learn if home-based bright-light treatment customized to participants’ circadian phase preference would impact their sleep, fatigue, daytime sleepiness, depression, and quality-of-life measures while undergoing chemotherapy DESIGN
Controlled pilot study PARTICIPANTS
A total of 18 women newly diagnosed with breast cancer stages I to III participated in this study, with 16 completing it in entirety. Their ages ranged from 29 to 68 years, with the majority being white/Caucasian and college-educated. Most were being treated for stage II breast cancer. People were excluded if they had a history of seasonal affective or psychiatric disorders, were on photosensitizing or sleep medications, or had other malignancies or cancer treatments, along with other exclusions. INTERVENTION
Investigators assigned participants to the experimental condition (bright blue-green light of 12,000 lux) or the control condition (dim red light of 5 lux). Participants received the light therapy for 30 minutes via a light visor each day at customized times depending on their circadian chronotype. Evening types began the light within 30 minutes of waking, and morning types had the light exposure between 7 to 8 pm. The light therapy was delivered for 21 consecutive days after the second cycle of chemotherapy. STUDY PARAMETERS ASSESSED
Investigators collected a variety of both subjective and objective measures. They collected baseline data prior to participants’ initiating their second cycle of chemotherapy, and they performed final data collection on the day of the third chemotherapy treatment.
By Catherine Darley, ND Subjective measures included the Patient-Reported Outcomes Measurement Information System (PROMIS), which measures fatigue. Subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI), and daytime sleepiness was assessed using the Epworth Sleepiness Scale (ESS). The Patient Health Questionnaire (PHQ-9) measured depression. Quality of life was measured using the European Organisation for Research and Treatment of Cancer-Quality of Life Questionnaire (EORTC QLQ-C30). Sleep was assessed objectively using ambulatory polysomnography (PSG). PRIMARY OUTCOME MEASURES
Investigators computed the relative change from baseline data to post-test data for both groups. Also a between-group analysis was done using 2 sample t-tests. KEY FINDINGS
The experimental group had meaningful improvements in their sleep, both subjectively and objectively. Subjectively, falling asleep took less time—only 10 minutes in the experimental group versus 20 minutes in controls (P=0.045). This was corroborated by the PSG data (14 vs 63 min) from the 7 participants who used the PSG at home. Polysomnography showed a longer sleep time of 467 minutes and greater sleep efficiency at 74% in those who received bright light, versus 315 minutes total sleep and only 58% sleep efficiency in the control group. While these differences did not reach statistical significance, the trends in the short time period of the study warrant mention here. There was a 30% relative decrease in depression for those in the bright light group, and a 24% relative increase in the controls, but again these did not reach statistical significance. Quality of life was less negatively impacted by chemotherapy for those in the intervention group, with symptom intensity (as reported in the EORTC questionnaire scores) increasing 33% versus 166% in the control group. Fatigue levels did not change with bright-light therapy, despite apparently better sleep.
18 ©2021 NATURAL MEDICINE JOURNAL. ALL RIGHTS RESERVED. NMJ, OCTOBER 2021 SUPPLEMENT—VOL. 13, NO. 101 (SUPPL)
