A Bayesian network meta analysis: evaluating the efficacy, recurrence rate, and safety of various therapies in granulomatous mastitis

Abstract Background Granulomatous mastitis (GM) is a rare, chronically relapsing inflammatory breast disease for which no universally accepted treatment standard exists. Although corticosteroids, surgery, methotrexate and other modalities are widely used, the regimen that simultaneously optimises efficacy, relapse control and safety remains unclear. Methods Six databases (PubMed, Embase, Cochrane Library, Scopus, ClinicalTrials.gov, and Google Scholar) were systematically searched from inception to 29 September 2025. Eligible studies included retrospective or prospective cohort studies evaluating at least one treatment for granulomatous mastitis (GM) and reporting relevant outcomes. The methodological quality of all included studies was assessed using the Newcastle–Ottawa Scale (NOS). Statistical analyses were performed using Stata 17.0 and R 4.4.2; a Bayesian network meta-analysis was conducted with the gemtc package. The primary outcome was relapse rate (RR); secondary outcomes were complete response (CR) and objective response rate (ORR). Two prespecified sensitivity analyses were performed to assess robustness: (1) restricting the analysis to high-quality studies (NOS score ≥ 7), and (2) limiting the relapse rate analysis to studies with a median follow-up duration of ≥ 12 months. Results We included 19 cohort studies enrolling a total of 1,559 patients with granulomatous mastitis. Compared with systemic corticosteroids, the combination of surgery and systemic corticosteroids significantly improved complete response (OR = 9.46, 95% CrI 1.22–74.47). Triple therapy—comprising systemic corticosteroids, local corticosteroids, and surgery—was associated with a significantly lower relapse risk (OR = 0.120, 95% CrI 0.020–0.709). No other treatment regimens demonstrated statistically significant benefits for the primary outcomes. In terms of safety, the adverse event rate was lower with surgery + systemic corticosteroids (18.6%) than with systemic corticosteroids alone (23.73%), whereas surgery alone was associated with a higher rate (33.3%). Sensitivity analyses support the robustness of our main findings. Conclusions This study suggests that multimodal combination therapies are generally superior to monotherapy regimens. Among them, surgery combined with systemic corticosteroids demonstrated notable advantages in both complete response rate and safety profile and ranked among the top strategies for relapse prevention. However, these findings are exploratory in nature and warrant validation through additional high-quality clinical studies.