Efficacy of Mindfulness-Based Interventions on Anxiety and Sleep Quality in Patients with Breast Cancer: A Systematic Review and Meta-Analysis

INTRODUCTION: Patients with breast cancer commonly experience anxiety and sleep disturbance during and after treatment, and these symptoms are closely interrelated, negatively affecting the quality of life. Mindfulness-based interventions (MBIs) have been increasingly used as a nonpharmacological supportive approach. This systematic review and meta-analysis aimed to evaluate the effects of MBIs on anxiety and sleep quality in patients with breast cancer. METHODS: A systematic search of PubMed, Web of Science, Cochrane Library, CINAHL, and Embase was conducted up to May 15, 2025. Random-effects meta-analysis was used to estimate standardized mean differences (SMDs) with 95% confidence intervals (CIs). Risk of bias was assessed using the Cochrane RoB 2.0, and the certainty of evidence was evaluated with Grading of Recommendations, Assessment, Development, and Evaluation. RESULTS: Twenty-four randomized controlled trials (RCTs) including 3,212 participants were analyzed. MBIs significantly reduced anxiety compared with control groups receiving usual care, no intervention, or wait-list conditions (SMD: -0.47, 95% CI: -0.62 to -0.32), whereas no significant effect was observed for sleep quality. Subgroup analysis indicated that intervention duration accounted for 55.5% of the heterogeneity in anxiety outcomes. All studies were rated as having some concerns regarding risk of bias, primarily due to self-reported outcomes and lack of blinding. Certainty of evidence was moderate for anxiety and low for sleep quality. DISCUSSION: MBIs appear to be effective in reducing anxiety among patients with breast cancer; however, no significant effect was observed for sleep quality. All included studies were rated as having some concerns regarding risk of bias, and the limited reporting of adverse events represents a limitation of the evidence. In addition, substantial heterogeneity in sleep quality outcomes and the limited number of included RCTs restrict exploration of heterogeneity sources and limit generalizability. Further high-quality well-designed RCTs are needed to strengthen and confirm the evidence.