Effect of Increased Light Exposure on Fatigue in Breast Cancer

Trial Information

Effect of Increased Light Exposure on Fatigue in Breast Cancer

Patients treated with chemotherapy complain of poor sleep, fatigue and depression. Our
preliminary research suggests that these symptoms may all be related, that chemotherapy
disrupts circadian rhythms which may exacerbate the poor sleep and fatigue and that during
chemotherapy, women are not exposed to much bright light which likely also contributes to
the disruption of rhythms. One of the easiest circadian rhythms to measure is sleep/wake
activity and the easiest way to synchronize this rhythm is with bright light treatment. It
is well established that bright light exposure will make rhythms more robust, and the
correct timing of the light exposure will have an alerting effect.

We hypothesize that after bright light treatment compared to dim light treatment during
three cycles of chemotherapy: fatigue (measured by the Multidimensional Fatigue Symptom
Inventory), depression (measured by the Center of Epidemiological Studies-Depression scale),
functional outcome scores (measured by the Functional Outcome of Sleep Questionnaire and by
the Functional Assessment of Cancer Therapy-Breast), and sleep measures (measured by
actigraphy, e.g., total sleep time, total wake time, bouts of sleep, napping) will all be
improved. We also hypothesize that circadian rhythms (measured by actigraphy) will be more
robust and more synchronized.

The aims are to examine the effect of bright light treatment on subjective measures of
fatigue, mood and functional outcome experienced during chemotherapy, to examine the effect
of bright light treatment on the quality and quantity of sleep during chemotherapy, to
examine the effect of bright light treatment on sleep/wake rhythms during chemotherapy.
Women with breast cancer stages I-III scheduled to begin chemotherapy will be recruited.
Wrist actigraphy data (for the measurement of sleep/wake activity) will be collected for
three consecutive days and nights immediately preceding chemotherapy and questionnaire data
(fatigue, mood, quality of life, functional outcome, sleep) will be collected during this
same time period. Half the women will be randomized to receive bright light and the other
half to dim red light as a control. Daily bright light or dim light treatment will be
administered during cycles 2, 3 and 4 of chemotherapy and all measures (actigraphy and
questionnaires) will be repeated during the first and last weeks of cycle 1 and cycle 4
chemotherapy. If bright light can improve sleep rhythms and fatigue, then the quality of
life of these women is likely to improve.