Value of 18F-fluorodeoxyglucose uptake in positron emission tomography/computed tomography in predicting survival in multiple myeloma

We assessed the role of the maximum standardized uptake value (SUVmax) of bone marrow and the extramedullary lesion with the highest SUVmax in positron emission tomography/computed tomography (PET/CT) of newly diagnosed multiple myeloma (MM) patients in predicting overall survival (OS). A total of 61 newly diagnosed patients (55 MM and 6 plasmacytoma) were enrolled in the study [37 men and 24 women with a median age of 57 years (range 28-80 years)]. The SUVmax of bone marrow and the extramedullary lesion in PET/CT was correlated with the levels of β2-microglobulin, C-reactive protein (CRP), albumin, creatinine, per cent of bone marrow plasma cells, serum free light chain (FLC) ratio, International Staging System (ISS) score and Durie-Salmon stage. The extramedullary lesion with the highest SUVmax showed significant correlation with bone marrow fluorodeoxyglucose (FDG) uptake (p = 0.027) and near significant correlation with ISS (p = 0.048). Bone marrow SUVmax correlated significantly with the per cent of bone marrow plasma cell count (p = 0.024), CRP (p = 0.012) and ISS (p = 0.013). In stage III MM the mean values of SUVmax in extramedullary lesions were significantly higher than stages I and II (6.23 ± 6.32 vs 2.85 ± 3.44, p = 0.023). The serum FLC ratio did not show any correlation with SUVmax of lesions and bone marrow (p > 0.05). Forty-four MM patients with FDG-positive lesions in PET/CT showed inferior 5-year estimated survival (61.73%) when compared to 11 patients without FDG-positive lesions, all of whom were alive (p = 0.01). In multivariate analysis an extramedullary lesion with the highest SUVmax was the only independent predictor of OS (p = 0.03). PET/CT allows identification of high-risk myeloma patients, and extramedullary lesions with the highest SUVmax independently predict inferior OS. (orig.)