PurposeWe aimed to compare the clinical characteristics, efficacy and survival of newly diagnosed extramedullary multiple myeloma patients (EMM) between single and multiple sites invasion.MethodsA total of 90 EMM patients were included. The characteristics including gender, age, Durie-Salmon stage, ISS stage, hemoglobin, blood calcium, creatinine, M-protein types, β2-microglobulin, lactate dehydrogenase and so on were analyzed. We compared the overall remission rates (ORR) in patients with

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... e site invasion and multiple sites invasion. Progression free survival (PFS) and overall survival (OS) were also compared.ResultsPatients with multiple sites invasion had higher lactate dehydrogenase than single site invasion (179.0U/L vs. 154.7U/L, P=0.016). The ORR in patients with single site invasion (72.1%) was not significantly higher than multiple sites invasion (68.2%) (P=0.690). In patients with multiple sites invasion, PI-based regimen (78.9% vs. 33.3%, P=0.035) or PI combined with IMiD regimen (84.6% vs. 33.3%, P=0.026) could achieve superior efficacy than routine chemotherapy. Among patients with single site invasion, the COX model analysis showed that proteasome inhibitors combined with immunomodulators could significantly improve the PFS (HR=0.080, 95%CI: 0.007-0.855, P=0.037). Among patients with multiple sites invasion, the associations of RISS 3 with poor PFS (HR=4.081, 95%CI: 1.533-10.865, P=0.005) and OS (HR=13.295, 95%CI: 3.219-54.907, P=0.000) were showed.ConclusionRISS stage 3 was possibly associated with poor survival of extramedullary multiple myeloma patients with multiple sites invasion. We propose a prospective and large-sample study to explore the effects of new drugs and autologous hematopoietic stem cell transplantation on survival of patients at RISS stage 3.