Restoring Child Cancer Survivors’ Natural Rhythms
Our Researcher: Valerie E. Rogers, PhD, RN, CPNP
By Dan Mezibov
Survival of childhood cancers is on the rise, with more than 80 percent of young patients surviving for at least five years post-treatment across all types of the disease. But despite the success, treatment — particularly chemotherapy — can cause delayed effects. Sixty percent of childhood cancer survivors report at least one chronic condition, such as persistent fatigue.
Moreover, cancer treatment is known to upset our natural circadian balance — the internal rhythms that align the body’s functioning with the earth’s day-night cycle and regulate everything from temperature and blood pressure to hormone production. Disturbing that schedule can trigger irregular sleep-wake cycles, and in cancer patients it has also been associated with greater fatigue, poorer response to treatment, quicker relapse, and an increased risk of death.
“Circadian rhythms are important to how you respond to therapy, and light is the most important external cue to reset those rhythms,” says Valerie Rogers, PhD, RN, CPNP, assistant professor at UMSON and a researcher specializing in sleep disorders in children with cancer. Keeping circadian activity at a healthy balance is especially critical in the first five years after completing chemotherapy, when the risk of relapse and death is highest, Rogers explains.
Developed originally to help adults with seasonal affective disorder improve their moods during winter months when sunlight is diminished, therapy using bright, white lights has been shown to prevent deterioration of circadian activity rhythms and reduce fatigue during chemotherapy in breast cancer patients and in adult cancer survivors. The technique, however, had never been tested in teens with cancer.
With $100,000 from the Alex’s Lemonade Stand Foundation, Rogers is conducting a two-year study to evaluate circadian rhythms in 30 adolescents aged 13-18 who are less than five years post-chemotherapy. The teens’ circadian activity rhythms are tracked on an accelerometer, a device worn on their wrists, and compared to those of 30 healthy controls to determine if their rhythms are dysregulated.
Based on that analysis, in the study’s second phase a subset of 10 cancer survivors who display poor sleep quality, irregular sleep-wake patterns, and other signs of circadian disruptions are treated with light therapy in their homes. For 30 minutes every morning over four weeks, the patients sit facing a portable light box while eating breakfast, reading, or doing other activities. Circadian readings are taken at baseline and again at two- and four-week intervals to determine if the light therapy has produced any changes.
“We know that children and adolescents on chemotherapy demonstrate dysregulated circadian activity rhythms,” Rogers says. What’s less clear, she explains, is how long it takes those rhythms to recover to normal — or if they ever do.
Indeed, Rogers adds, researchers are now exploring ways to time chemotherapy and surgery to patients’ circadian activity to produce better outcomes, with fewer drugs and side effects. Meanwhile, light therapy can be done easily in the home; if proven effective, Rogers says, it may provide a relatively low-burden, low-cost, non-drug treatment for alleviating circadian activity disruptions and fatigue, two modifiable risk factors in cancer treatment. “Half a million people are survivors of childhood cancer,” she points out. “Nurses aren’t looking for the cure, but we are looking for ways to make that cancer livable and improve a patient’s quality of life.”