We assessed the role of the maximum standardized uptake value (SUV(max)) of bone marrow and the extramedullary lesion with the highest SUV(max) 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 SUV(max) of bone marrow and the extramedullary lesion in PET/CT was correlated with the levels of β(2)-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 SUV(max) showed significant correlation with bone marrow fluorodeoxyglucose (FDG) uptake (p = 0.027) and near significant correlation with ISS (p = 0.048). Bone marrow SUV(max) 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 SUV(max) 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 SUV(max) 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 SUV(max) 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 SUV(max) independently predict inferior OS.