Unveiling the enigma: understanding the complex disease course of granulomatous mastitis and seeking ways to shorten it.

Background: Granulomatous mastitis is an infrequent and intricate ailment. Limited knowledge exists regarding how granulomatous mastitis progresses and its impact on disease management. We aim to prospectively capture symptoms in the general population to accurately ascertain the duration of illness and the prevalence of long-lasting symptoms. Methods: This study reports data from 169 prospectively enrolled real-world patients with pathologically confirmed granulomatous mastitis. Patients were enrolled after screening according to the inclusion and exclusion criteria. Patients were followed-up every 2-4 weeks during treatment, then every 3-6 months (Year 1) and 6-12 months (Year 2). Outcomes included symptom resolution, disease course, and relapse. Associations between clinical variables and outcomes were assessed using appropriate statistical models, with significance defined as P<0.05. Results: The median disease course of granulomatous mastitis was 257 days (range, 55-1,500 days), with the majority of disease regression occurring within a span of 6 months subsequent to diagnosis; 72.78% of patients preferred steroids as the initial treatment. The use of steroids was associated with a shorter disease course after adjusting for age, lump size, abscess, and sinus formation (P=0.02). Abscess formation was observed in 58.57% of patients. Notably, abscess formation during disease progression contributed to a prolonged disease course (358.67 Conclusions: Our findings highlighted the heterogeneity of granulomatous mastitis disease course and emphasized the importance of steroid usage in shortening disease course. Avoiding abscess and sinus formation, early steroid usage during granulomatous mastitis treatment might be beneficial. These evidences provide novel insights and supports the use of steroids in patients with granulomatous mastitis for modulating their immune response. Studies are urgently needed to further elucidate the role of steroid in granulomatous mastitis management.