Circadian Rhythms, Fatigue and Bright Light Therapy in Adolescent Cancer Survivors
Cancer treatment causes circadian rhythm (24-hour biological rhythms) dysregulation in adults. Circadian activity rhythms (CAR), the rhythms of our daily movement, are a useful measure of our circadian rhythms. In adult cancer patients, dysregulated CAR is associated with greater fatigue, and decreased quality of life and responsiveness to therapy, and often continues during survivorship.
Little is known about CAR in childhood cancers. We recently showed that children and adolescents with leukemia experienced dysregulated CAR and increased fatigue when taking dexamethasone, a chemotherapy drug. This suggests that circadian dysregulation in children and adolescents might be similar to that in adult cancer patients.
Effects of cancer treatment can linger after completing chemotherapy. Studying CAR of childhood cancer survivors presents an opportunity to improve health outcomes. Bright white light (BWL) is a therapy used to treat depression and circadian rhythm disorders that has improved CAR and fatigue in adult cancer patients, and fatigue in adult cancer survivors. BWL has never been tested in adolescent cancer survivors.
This study compares CAR of 30 adolescent cancer survivors and 30 age-matched healthy controls, to evaluate whether CAR of survivors shows greater dysregulation than CAR of controls. A subset of 10 adolescent survivors with signs of dysregulated CAR will receive a BWL intervention for four weeks, to test the feasibility and effectiveness of BWL in improving CAR and fatigue. If BWL is shown to be feasible and effective in adolescents, with minimal side effects, it presents an easily implemented non-drug therapy for improving post-treatment CAR and fatigue.
"Strong circadian rhythms are necessary for good health. Weakening of these rhythms is common in
adult cancer patients and is associated with poor health outcomes. We previously identified disturbed
circadian activity rhythms, the rhythms of daily activity and rest, in children with leukemia. In our study,
funded through an ALSF Nurse Researcher Discovery Grant, we extend this finding to explore the
recovery of these rhythms in adolescents who have completed treatment for childhood cancer. We also
test a morning bright light intervention, to explore its feasibility and effect on recovery of strong
circadian activity rhythms. We suspect that circadian rhythms recover slowly on completing cancer
therapy, and are excited to test a non-medication treatment that might improve circadian rhythms, and
potentially health outcomes, in childhood cancer survivors." - Valerie Rogers