Assessing the impact of app-delivered lighting interventions on fatigue in three populations of cancer patients

ABSTRACT
Cancer patients often experience disruptions to their bodyandapos;s internal, circadian clock over the course of
treatment, which contribute to worsened side-effects and quality of life. These side-effects include cancer-
related fatigue (CRF), which affects millions of patients and can persist for months to years after the end of
treatment. Despite the pervasiveness of CRF, the guidelines for treating it are largely limited to exercise,
cognitive behavioral therapy, and other psychosocial interventions, which present challenges of compliance,
accessibility, and scalability. Light therapy, however, has a lower barrier to entry and has shown promise as a
way of reducing symptoms of fatigue in cancer patients by targeting circadian pathways. Light is the primary
input to the bodyandapos;s internal clock. By timing light exposure-- e.g., increasing morning light and decreasing light
at night-- lighting interventions can bolster the clock, improving fatigue and consolidating sleep. The
advantages of a more robust clock may also go beyond fatigue and sleep, as better outcomes in cancer
patients are associated with less disrupted circadian rhythms. Despite the potential value in light interventions,
several limitations have held back their wide-spread adoption as a treatment. There is limited awareness about
how light timing affects the circadian clock, which is complicated by the fact that the clockandapos;s sensitivity to light
changes over the course of the day. In addition, any lighting interventions need to be tailored to an individualandapos;s
“personal time zone” (i.e., their circadian clockandapos;s current state) in order to be effective. Two individuals living in
the same location may need light at markedly different times if their daily schedules are sufficiently different, or
if oneandapos;s circadian clock is much more disrupted than the other. The work in this proposal is a clinical trial to test
an app (“SHIFT”) that recommends personalized lighting interventions to reduce fatigue in cancer patients. 138
patients will be recruited from the University of Michiganandapos;s Cancer Center and provided with the SHIFT app, as
well as a pair of blue-blocking glasses and a Fitbit wearable device. The patients will be tracked longitudinally,
with fatigue as the primary outcome, and sleep disturbances, sleep aid usage, mood, and anxiety as
secondary outcomes. We expect to observe statistically significant differences in fatigue as a result of targeted
lighting interventions. The final product will be a quantification of the SHIFT appandapos;s ability to improve fatigue in
cancer patients and a roadmap for iteratively improving the app.PROJECT NARRATIVE
Fatigue is a major problem for cancer patients, and one that can persist long after treatment ends. Recent work
has demonstrated that light therapy may mitigate or reduce fatigue levels in both cancer patients and cancer
survivors. This proposal seeks to assess how lighting interventions distributed through a mobile app affect
fatigue, sleep, and quality of life across three populations of cancer patients.