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 (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 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 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.