Efficacy and Tolerability of Methotrexate for Idiopathic Granulomatous Mastitis: A Systematic Review and Meta‐Analysis

Background: Idiopathic granulomatous mastitis (IGM) is a challenging inflammatory breast disease with limited standardized treatment guidelines. Methods: This meta-analysis systematically evaluated the efficacy and safety of methotrexate (MTX) in IGM, pooling data from observational studies. We assessed complete remission rates, recurrence rates, and severe side effects leading to MTX discontinuation using both common and random effects models, accounting for heterogeneity. Results: = 81.4%). Combination therapy showed a higher complete response rate in the common effect model (78.0%, 95% CI: 71.4-83.3%) compared to monotherapy (46.6%, 95% CI: 34.2-59.3%), though this difference was not significant in the random effects model. The overall pooled proportion of severe side effects leading to MTX discontinuation was low at 1.23% (95% CI: 0.40-3.74%) in the common effect model and 0.51% (95% CI: 0.03-9.37%) in the random effects model, with no significant heterogeneity. In controlled studies, MTX showed no significant difference in complete remission compared to steroid-containing controls. Conclusion: Based on a pooled complete response rate of 61.6%, MTX appears to be an effective and well-tolerated treatment for IGM, though substantial heterogeneity exists in uncontrolled studies.