Light Therapy May Alleviate Depressive Symptoms Among Cancer Survivors

Preliminary data from a small randomized study showed light therapy decreased depressive symptoms and normalized circadian rhythms among cancer survivors.

Investigators from Icahn School of Medicine at Mount Sinai conducted the study in collaboration with researchers at Northwestern University, University of Iowa, University of California, San Diego, and Reykjavik University in Iceland.

The analysis included 54 cancer survivors, each of whom received a light box that they were asked to use daily. The light boxes given to participants in the experimental group emitted a bright white light, and those given to participants in the control group emitted a dim red light.

Study participants exposed to the bright white light experienced improvement in depressive symptoms, cancer-related fatigue and circadian activity rhythms, whereas those exposed to the dim red light experienced no change in symptoms.

Study researcher Heiddis Valdimarsdottir, PhD, associate professor of oncological sciences at Icahn School of Medicine, spoke with HemOnc Todayabout the potential benefits of light therapy for cancer survivors and what future research in this area will entail.

Question: What was the purpose of your research ?

Answer: Many cancer survivors suffer from cancer-related fatigue and depressive symptoms, even long after treatment has ended. One reason these patients are depressed or fatigued might be because their circadian rhythm is off. Cancer or its treatment can affect circadian rhythm or our biological clock. For example, levels of certain hormones such as cortisol — which are high in the morning and make us more alert — gradually decrease throughout the day. Among some cancer survivors, this does not happen. Instead, cortisol remains flat throughout the day. Another hormone, melatonin, which helps us sleep, is higher during the day among some cancer survivors. Light is one of the strongest stimulators that adjust our biological clock. Therefore, we tested if light therapy would adjust the biological clock and improve depressive symptoms and restore the circadian rhythm among cancer survivors.

Q: Were you surprised by any of the outcomes ?

A: We were surprised mainly by how incredibly strong the effects were. We did not expect light therapy to be so powerful, but we have to be careful when interpreting our findings because they are so preliminary.

Q: Can you describe what bright light therapy entails? How might it be incorporated into formal treatment ?

A: We gave study participants a small light box and asked them to use it for 30 minutes every morning for 4 weeks. The light had to be shined indirectly at the participant, not in their eyes. Participants could read the morning paper, drink their coffee or be on their computer. By doing this, we anticipated that the light would affect the circadian rhythm or restore it, which, in turn, would affect both depressive symptoms and fatigue. We think patients who are depressed or fatigued have less energy to go out of the house. Therefore, they are not getting enough daylight, which will affect their mood. Once we have tested this further and shown that this treatment is effective, it can easily be incorporated into cancer treatment.

Q: What effect does mood have on the overall outcomes of patient s with cancer ?

A: Depressive symptoms affect quality of life for anyone. Being depressed is a miserable feeling, and it can affect one’s whole well-being. Results of meta-analysis of results from a large number of related studies showed thatdepression can affect biological processes related to cancer progression and possibly affect survival.

Q: Is this something that would be effective for all patients?

A: We cannot definitively say ‘yes’ yet. So far, the preliminary results show it is effective for all patients.

Q: What is your hope for future research on this topic?

A: William H. Redd, PhD, professor at Mount Sinai School of Medicine, and our team received a grant from NIH that will allow us to expand our study with 200 cancer survivors. We will also be able to look at biological mechanisms whereby light affects depression and fatigue. We think we understand that light affects the circadian rhythm, which then affects one’s depressive symptoms and fatigue; however, we were not able to address that in our preliminary study. In our larger study, we can address this in better detail and determine for whom light therapy might be most effective.

Q: What overall take-home message can you offer?

A: Given the preliminary nature of our study, we cannot make any recommendations regarding light therapy. But, if you are a cancer survivor who is feeling fatigued or depressed, you might consider talking to your physician about using a light box. by Jennifer Southall

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