Visual and volumetric parameters by 18F-FDG-PET/CT: a head to head comparison for the prediction of outcome in patients with multiple myeloma.

In multiple myeloma (MM) patients, 18F-FDG-PET/CT allows either the detection of disease spread by using visual parameters based on the Italian Myeloma criteria for PET Use (IMPeTUs) or the direct measurement of metabolic tumor burden by volume-based parameters such as metabolic tumor volume (MTV). The purpose is to evaluate the contribution of visual and volumetric parameters in the prediction of progression-free survival (PFS) and overall survival (OS) in MM patients. Forty-seven patients in stage IIIA who had undergone whole-body 18F-FDG-PET/CT were retrospectively evaluated. In each patient, visual parameters were determined and compared with volumetric parameters for PFS and OS prediction after a mean follow-up period of 53 months. Among the visual and volumetric parameters tested, a statistically significant difference was found between maximum standardized uptake value, MTV, total lesion glycolysis, and number of lytic lesions of patients with (n = 26) or without (n = 21) progression (p = 0.0400, p = 0.0065, p = 0.015, and p = 0.0220, respectively) and of dead (n = 24) vs survivors (n = 23) (p = 0.0171, p = 0.0037, p = 0.0060, and p = 0.0270, respectively). At univariate and multivariate analysis, MTV and hemoglobin were predictive of both PFS (p = 0.008) and OS (p = 0.0026). The best MTV discriminative value assessed by receiver operating characteristic curve analysis for predicting both PFS and OS was 39.4 ml. By Kaplan-Meier analysis and log-rank test, PFS and OS were significantly better in patients with MTV ≤ 39.4 ml (p = 0.0004 and p = 0.0001, respectively) as compared with those having an MTV higher than the cutoff. The volume-based parameter MTV determined by 18F-FDG-PET/CT may be used in the prediction of PFS and OS in myeloma patients.