Light treatment prevents fatigue in women undergoing chemotherapy for breast cancer

Abstract

Purpose: Fatigue is one of the most disturbing complaints of cancer patients and is often the reason for discontinuing treatment. This randomized controlled study tested the hypothesis that increased morning bright light, compared to dim light, would result in less fatigue in women with breast cancer undergoing chemotherapy.

Methods: Thirty-nine women newly diagnosed with stage I-III breast cancer were randomized to either bright white light (BWL) or dim red light (DRL) treatment and were instructed to use the light box for 30 min every morning throughout the first four cycles of chemotherapy. The Multidimensional Fatigue Symptom Inventory was administered prior to the start of chemotherapy (baseline), during the chemotherapy treatment week of cycle 1 (C1TW), the last week (recovery week) of cycle 1 (C1RW), the chemotherapy treatment week of cycle 4 (C4TW), and the last week (recovery week) of cycle 4 (C4RW).

Results: The DRL group reported increased fatigue at C1TW (p = 0.003) and C4TW (p < 0.001) compared to baseline, while there was no significant change from baseline in the BWL group. A secondary analysis showed that the increases in fatigue levels in the DRL group were not mediated through nor associated with changes in sleep or in circadian rhythms as measured with wrist actigraphy.

Conclusions: The results of this study suggest that morning bright light treatment may prevent overall fatigue from worsening during chemotherapy. Although our hypothesis that overall fatigue would improve with bright light treatment was not supported, the lack of deterioration in total fatigue scores suggests that bright morning light may be a useful intervention during chemotherapy for breast cancer.

Figure 1a and b

Model of a negative feedback loop of chemotherapy leading to fatigue, which leads to less time spent outdoors, which leads to less bright light exposure, which could lead to increased fatigue (Fig 1a). We hypothesized that the addition of morning bright light would break this cycle (Fig. 1b).

Figure 1a and b

Model of a negative feedback loop of chemotherapy leading to fatigue, which leads to less time spent outdoors, which leads to less bright light exposure, which could lead to increased fatigue (Fig 1a). We hypothesized that the addition of morning bright light would break this cycle (Fig. 1b).

Figure 2

Consort table of participant recruitment and retention

Figure 3

MFSI-sf total fatigue scores for the BWL treatment group and the DRL treatment group at five time points (BL = pre-chemotherapy baseline; C1TW = cycle 1 chemotherapy treatment week; C1RW = cycle 1 recovery week; C4TW = cycle 4 chemotherapy treatment week; C4RW = cycle 4 recovery week). There was a group × time interaction at C4TW (p=0.022) suggesting that the change from baseline in the DRL group was significantly different than the change in the BWL group. The DRL group reported increased fatigue at C1 TW (p=0.003) and C4 TW (p<0.001) compared to baseline while there was no significant change from baseline in the BWL group.