Effect of bright light therapy on cancer-related fatigue and related symptoms: A systematic review and meta-analysis of randomized controlled trials

Objective: Cancer-related fatigue (CRF) is a common side effect in cancer patients, possibly due to disrupted circadian rhythms. While bright light therapy (BLT) is known to modulate circadian rhythms, its role in mitigating CRF remains unclear. This study examined the impact of BLT on CRF and other related symptoms. Methods: PubMed, Embase, Cochrane Library, and SCOPUS databases were searched. The trials were selected according to the PRISMA guidelines. The severity and quality of CRF and related symptoms were investigated in post-BLT intervention. Results: Twelve trials involving 691 were included. BLT significantly reduced CRF (SMD = −0.92, 95% CI: −1.45 to −0.40, p < 0.00001, I2 = 90%) and insomnia (SMD = −2.80, 95% CI: −4.61 to −0.98, I2 = 0%). Subgroup analyzes were performed based on various factors including light illuminance and intervention duration. BLT was found to be effective in both preventing and treating CRF, though it did not significantly enhance sleep quality, depression, and quality of life (QoL). Conclusion: BLT is a promising intervention for managing CRF in cancer patients. Its efficacy in improving sleep quality, and insomnia, reducing depression, and enhancing QoL requires further exploration. A 4-week BLT intervention with ≥10,000 lx is recommended for preventing and treating CRF, with longer or less intense interventions also showing effectiveness. Otherwise, BLT exhibited minimal adverse effects.