The effect of mindfulness-based meditation on the immune function of breast cancer patients: A systematic review and three-level meta-analysis

Mindfulness-based meditation has been proposed as a complementary approach to support immune function in cancer patients, yet its biological effects remain unclear and heterogeneous across biomarkers. This study systematically reviewed and quantitatively synthesized empirical evidence using a three-level random-effects meta-analysis to account for statistical dependence among multiple effect sizes. A systematic search through December 2024 identified 11 reports (9 unique studies) with 110 effect sizes (N = 991). Eligible studies involved cancer patients (primarily breast cancer, >87 %) undergoing mindfulness-based meditation interventions and reporting immune-related biomarkers. Hedges’ g was used to calculate effect sizes. In the first-round analysis, based on RCT post-test data, mindfulness-based meditation showed a small but significant effect on immune function (g = 0.100, p = .026, 95 % CI [0.012, 0.188]). The second-round analysis, incorporating pre–post data from both RCTs and single-group studies, yielded a non-significant effect (g = 0.067, p = .114, 95 % CI [–0.016, 0.150]). Among tested moderators, only country significantly influenced effect sizes, whereas intervention duration, intervention type, and biomarker type did not. These findings suggest that mindfulness-based meditation may modestly regulate immune function in cancer patients by reducing inflammation, increasing immune cell counts and activity, and potentially promoting telomere length and activity. More rigorously designed studies with standardized biomarker reporting and more diverse populations are needed to clarify its therapeutic potential.