Risk Factors and Prognosis of Extramedullary Disease in Newly-Diagnosed Multiple Myeloma Patients

Extramedullary Disease (EMD) in Multiple Myeloma (MM) is detected in 4-7% of patients at the time of diagnosis and increases to 6-20% in relapsed/refractory patients. In our study, we aimed to determine the risk factors for EMD, and the effects of bone marrow (BM) fibrosis on survival in newly diagnosed MM patients presenting with EMD at the time of diagnosis. A total of 189 MM patients who were newly diagnosed between November 2016 and September 2023 were included in the present study. EMD is defined as soft tissue plasmacytomas that occur due to hematogenous spread and have no contact with bone structures. EMD was detected in 21 (11.1%) of the 189 patients who were included in the present study. In multivariate analysis, the presence of fibrosis in the BM (OR: 3.45, 95% CI: 1.09-10.89; p= 0.032) were found to be independent risk factors for EMD. After a median follow-up period of 36 months, the median overall survival (OS) in patients with EMD was 13 months, and the median OS in those without extramedullary involvement was 77 months (HR: 3.09; 95% CI: 1.52-6.26, p= 0.002). No difference in OS was observed between patients with BM fibrosis (Grade 1-3) and patients without fibrosis (HR:1.04, 95% CI: 0.60-1.79; p= 0.885). As a result of the present study, it was found that BM fibrosis might be a predictive factor for the presence of EMD. A detailed examination for EMD might be required in newly diagnosed MM Keywords: Extramedullary Disease, Multiple Myeloma