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

## TL;DR

Methotrexate shows moderate effectiveness and good tolerance for treating idiopathic granulomatous mastitis, but results vary across studies.

## Contribution

A systematic review and meta-analysis evaluating methotrexate's efficacy and safety for idiopathic granulomatous mastitis using pooled observational data.

## Key findings

- Methotrexate achieved a pooled complete response rate of 61.6% for idiopathic granulomatous mastitis.
- Combination therapy showed higher complete response rates than monotherapy in some models.
- Severe side effects leading to methotrexate discontinuation were rare, at 1.23%.

## Abstract

Idiopathic granulomatous mastitis (IGM) is a challenging inflammatory breast disease with limited standardized treatment guidelines.

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.

Nine studies were included. In analyses without control groups, the pooled complete response rate for MTX was 61.6% (95% CI: 40.4–79.2%), with significant heterogeneity (I
2 = 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.

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.