A Morning Bright Light Therapy Intervention to Improve Circadian Health in Adolescent Cancer Survivors: Methods and Preliminary Feasibility.

Circadian rhythm disturbances are common among children with cancer, and are associated with poor health outcomes. Social zeitgeber theory suggests that intervening in the cascade of events that disrupt circadian rhythms may improve health outcomes. Light, most potently sunlight, is a "zeitgeber," or environmental cue instrumental in maintaining entrainment of circadian rhythms. Bright white light (BWL) therapy, a proxy for sunlight, has been used successfully to prevent deterioration of circadian rhythms in adult cancer patients, and to reentrain these rhythms in adolescents with circadian rhythm disorders. This study aimed to develop and assess preliminary feasibility of a BWL therapy intervention for supporting circadian health of adolescent cancer survivors. We hypothesized that adolescents could independently manage BWL in their home, coordinated by nurses using a mail-, phone- and internet-based format, with minimal side effects. Adolescents were instructed to use BWL for 30 minutes daily on awakening, for 28 days. Actigraphs, measuring the circadian activity rhythms of sleep and wake, were worn for 7 days at baseline and Week 4. Adverse events were screened serially. Analyses were descriptive and nonparametric. Eight adolescents participated. On average, BWL was used on 61% of days, for 15 minutes per day. Adverse events were generally mild, although one participant discontinued BWL due to persistent BWL-related nausea. This nurse-guided remote BWL therapy intervention in adolescent cancer survivors demonstrated preliminary feasibility. Future studies with larger samples are required to verify the feasibility of this study, and to determine its safety and effectiveness in supporting circadian activity rhythms.