Ductal lavage followed by observation versus oral corticosteroids in idiopathic granulomatous mastitis: A randomized trial

Oral corticosteroids represents the most prevalent treatment for idiopathic granulomatous mastitis. Ductal lavage with triamcinolone acetonide and antibiotics followed by observation (DL-OBS) has emerged as a novel strategy, but a comparison of them remains lacking. Here in this multicenter, open-label, non-inferiority, randomized trial (ClinicalTrials.gov identifier: NCT03724903), we assigned 140 patients to oral corticosteroids (N = 71) and DL-OBS (N = 69), stratified by baseline M-score. The primary outcome is complete Clinical Response rate at 1 year. The non-inferiority margin is -15%. The primary outcome is 85.5% in DL-OBS and 87.3% in oral corticosteroids (difference: -1.8%; 95%CI, 13.2 to 9.5; P_{non-inferiority} = .01) in intention-to-treat population, and 92.6% vs 98.2% (difference -5.6%; 95%CI -13.4 to 2.2; P_{non-inferiority} = .01) in per-protocol population, respectively. The most common (>15%) adverse events were Cushingoid, epigastric pain and arthralgia in oral corticosteroids, and irregular menstruation in DL-OBS, respectively. Here, we report that DL-OBS shows similar efficacy to oral corticosteroids but with better safety profile.