Advanced cancer patients in a randomized clinical trial of night-simulating eyeglasses observed to have a normal 24-h circadian rhythm during chemotherapy.

Objectives: Cancer patients routinely exhibit dysfunctional circadian organization. Indeed, a dysfunctional circadian organization is a hallmark of advanced cancer. A cohort of advanced cancer patients undergoing chemotherapy was recruited to investigate whether manipulating exposure to blue light could restore or ameliorate their circadian organization. Methods: Thirty advanced metastatic cancer patients participated in a randomized crossover trial to evaluate whether blue light-blocking night-simulating eyeglasses could ameliorate a disrupted circadian organization better than sham eyeglasses. Circadian organization was evaluated by actigraphy and patients' self-reports of sleep, fatigue, and quality of life. Kruskal-Wallis tests compared patients' outcomes in circadian organization with a cohort of non-cancer, disease-free individuals with normal sleep as a negative control, and with advanced cancer patients with disrupted circadian organization as a positive control. Quality-of-life outcomes of the patients were compared with population-based controls (negative controls) and with cohorts of advanced cancer patients (positive controls). Results: Actigraphy measurements, self-reported sleep, fatigue levels, and quality-of-life outcomes of trial participants were similar to those of negative controls with a normal circadian organization, in spite of the trial patients' concurrent chemotherapy. Night-simulating glasses did not improve circadian organization. The 24-h correlation of day-to-day rhythms of rest and activity was 0.455 for the experimental eyeglasses and 0.476 for the sham eyeglasses (p = 0.258). Actigraphic and patient-reported outcomes compared favorably to outcomes of positive controls. Conclusion: The circadian organization of patients in this study unexpectedly resembled that of healthy controls and was better than comparison populations with disrupted circadian organization. The study clinic implements chronomodulated chemotherapy and a systematic, supportive integrative treatment protocol. Results suggest a need for further research on interventions for circadian rhythm. Although the study intervention did not benefit the participants, this work highlights the value of supporting circadian time structure in advanced cancer patients.

Nighttime use of special spectacles or light bulbs that block blue light may reduce the risk of cancer.

For more than 15 years evidence has been accumulating that there is a link between a lack of melatonin and cancer, especially breast, ovarian and prostate cancer. For a similar period it has been known that exposing the eyes to light when melatonin is normally flowing reduces or eliminates the flow. What is relatively new is that it is primarily the blue wavelengths that are responsible for loss of melatonin. Blocking these blue rays with amber glasses restores melatonin flow. Also new is the direct evidence, from analysis of the famous nurses' health study, that having more melatonin present in first morning urine is linked to a reduction in the incidence of breast cancer. This leads to the hypothesis that wearing amber glasses (or using blue-free light bulbs) for a few hours before bedtime maximizes melatonin production and reduces the risk of breast, ovarian and prostate cancer and possibly other cancers.