Association of increased microvessel density with skeletal extramedullary disease relapse in multiple myeloma patients who have skeletal extramedullary disease at diagnosis

The aim of the study was to investigate whether microvessel density (MVD) could be associated with skeletal extramedullary disease relapse (skeletal-EMDR) in patients with multiple myeloma (MM) who have skeletal-EMD at diagnosis. Seventy-nine newly diagnosed MM patients who have skeletal-EMD were retrospectively enrolled in this study. The 4-year cumulative incidence of skeletal-EMDR was 35.0%±8.3%. The 4-year probability of overall survival (OS) was 54.0%±7.6%. Multivariate analysis showed that skeletal-EMDR (HR = 4.144; 95% CI: 1.608–10.685; P = 0.003) was independently associated with inferior OS for the MM patients who have skeletal-EMD at diagnosis. The factors associated with skeletal-EMDR were MVD (HR = 3.990, 95%CI:1.136-14.018; P = 0.031), white blood cell (WBC) (HR = 0.262, 95% CI:0.090-0.769; P = 0.015), and the EMD sites involved at onset (HR = 0.263, 95% CI: 0.074-0.937; P = 0.039). The MVD in patients with thoracic and lumbar vertebrae as the involved sites at diagnosis was significantly lower than those with other sites involved (41.59 ± 14.39 vs. 60.82 ± 35.14, P=0.001). Our data suggest that increased MVD could be used to predict skeletal-EMDR, which is associated with inferior survival in patients with MM who have skeletal-EMD at diagnosis.