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 visualparametersbasedontheItalianMyelomacriteriaforPETUse (IMPeTUs) or the direct measurement of metabolic tumorburden by volume-based parameters such as metabolic tumor volume (MTV). The purpose is to evaluate the contributionof visual and volumetric parameters in the prediction of progression-free survival (PFS) and overall survival (OS) inMM patients. Forty-seven patients in stage IIIA who had undergone whole-body 18F-FDG-PET/CT were retrospectivelyevaluated. In each patient, visual parameters were determined and compared with volumetric parameters for PFS and OSprediction after a mean follow-up periodof 53 months. Among the visual and volumetric parameters tested, a statisti-cally significant difference was found between maximum standardized uptake value, MTV, total lesion glycolysis, andnumber of lytic lesions of patients with (n= 26) or without (n= 21) progression (p= 0.0400,p= 0.0065,p= 0.015, andp= 0.0220, respectively) and of dead (n=24)vssurvivors(n= 23) (p= 0.0171,p= 0.0037,p= 0.0060, andp=0.0270,respectively). At univariate and multivariate analysis, MTV and hemoglobin were predictive of both PFS (p= 0.008) andOS (p= 0.0026). The best MTV discriminative value assessed byreceiver operating characteristic curve analysis forpredicting both PFS and OS was 39.4 ml. By Kaplan-Meier analysis and log-rank test, PFS and OS were significantlybetter in patients with MTV≤39.4 ml (p=0.0004andp= 0.0001, respectively) as compared with those having an MTVhigher than the cutoff. The volume-based parameter MTVdeterminedby18F-FDG-PET/CTmaybeusedinthepre-diction of PFS and OS in myeloma patients.