WOMEN receiving chemotherapy for breast cancer experienced greater improvements in insomnia symptoms with cognitive behaviour therapy for insomnia (CBT-I) than without it, according to a randomised clinical trial.
The Sleep, Cancer, Rest trial was a 6-week, 2×2 factorial randomised controlled trial conducted across five metropolitan and regional hospitals in Australia between January 2021 and August 2024. The study included 219 women aged 18 years or older who were receiving chemotherapy for early or metastatic breast cancer.
Participants were randomised to CBT-I, bright light therapy (BLT), both interventions, or sleep hygiene education. All groups received sleep hygiene education. The interventions included a consultation, regular email contact, and a midpoint telephone call, while participants receiving BLT also used light glasses delivering 1500 lux.
A total of 208 women with available data were included in the modified intention-to-treat analysis.
Bright Light Therapy Shows No Overall Benefit
The study assessed insomnia using the Insomnia Severity Index (ISI) and fatigue using the Patient-Reported Outcomes Measurement Information System Fatigue score.
Insomnia symptoms improved significantly more among women receiving CBT-I than among those who did not receive CBT-I (ISI mean difference: −2.19 points; 95% CI: −3.33 to −1.05; P=0.002).
However, CBT-I did not produce a significant improvement in fatigue symptoms compared with non-CBT-I treatment (PROMIS-Fatigue mean difference: −0.90 points; 95% CI: −3.08 to 1.28; P=0.52).
BLT did not significantly improve either insomnia or fatigue compared with treatment without BLT. For insomnia, the mean difference was −0.88 points (95% CI: −2.02 to 0.26; P=0.26), while the mean difference for fatigue was −0.71 points (95% CI: −2.89 to 1.47; P=0.52).
Metastatic Breast Cancer Subgroup Shows Potential
Exploratory analyses produced different findings among women with metastatic breast cancer. In this subgroup, BLT was associated with greater improvements in both insomnia and fatigue compared with non-BLT treatment.
The mean difference in ISI score was −2.87 points (95% CI: −5.06 to −0.67; P=0.01), while the mean difference in PROMIS-Fatigue score was −5.16 points (95% CI: −9.57 to −0.76; P=0.02).
The researchers concluded that brief CBT-I may reduce insomnia symptoms in women undergoing chemotherapy for breast cancer, whereas BLT did not provide additional overall benefit for insomnia or fatigue. The exploratory findings in metastatic breast cancer warrant further investigation.
Reference
Do TT et al. Cognitive behavior vs bright light therapy for insomnia in women undergoing chemotherapy for breast cancer: a randomized clinical trial. JAMA Netw Open. 2026;9(8):e2630320.
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