Refractory and Recurrent Idiopathic Granulomatous Mastitis Treatment: Adaptive, Randomized Clinical Trial

Background: Idiopathic Granulomatous Mastitis (IGM) is mostly described as an autoimmune disease with high prevalence among Middle Eastern childbearing-age women. The current study aimed to evaluate the best treatment of choice in patients with resistant or recurrent IGM. Study Design: Patients with established recurrent or resistant IGM who were referred to the breast cancer research center from 2017 to 2020 were randomly assigned to either one of the following treatment groups: A (Best supportive care), B (corticosteroids: prednisolone), and C (methotrexate and low dose corticosteroids). This adaptive clinical trial evaluated radiological and clinical responses, as well as the possible side effects, on a regular basis in each group, with patients followed up for a minimum of 2 years. Results: A total of 318 participants, with a mean age of 33.52 ± 6.77 years, were divided into groups A (10 patients), B (78 patients), and C (230 patients). In group A, no therapeutic response was observed; group B exhibited a mixed response, with 14.1% experiencing complete or partial responses, 7.7% maintaining stability, and 78.2% experiencing disease progression. Accordingly, groups A and B were terminated due to inadequate response. In group C, 94.3% achieved complete response, 3% partial remission, and 2.7% no response. Among the entire patient cohort, 11.6% tested positive for anti-nuclear antibodies (ANA), 3.5% for angiotensin-converting enzyme (ACE), and 12.3% for erythema nodosum (EN). Notably, hypothyroidism was a prevalent condition among the patients, affecting 7.2% of the cohort. Furthermore, the incidence of common side effects was consistent across all groups. Conclusions: The most effective treatment option for patients with recurrent or resistant idiopathic granulomatous mastitis is a combination therapy involving steroids and disease-modifying antirheumatic drugs such as methotrexate.