PT - JOURNAL ARTICLE AU - Fonti, Rosa AU - Larobina, Michele AU - Del Vecchio, Silvana AU - De Luca, Serena AU - Fabbricini, Rossella AU - Catalano, Lucio AU - Pane, Fabrizio AU - Salvatore, Marco AU - Pace, Leonardo TI - Metabolic Tumor Volume Assessed by <sup>18</sup>F-FDG PET/CT for the Prediction of Outcome in Patients with Multiple Myeloma AID - 10.2967/jnumed.112.106500 DP - 2012 Dec 01 TA - Journal of Nuclear Medicine PG - 1829--1835 VI - 53 IP - 12 4099 - http://jnm.snmjournals.org/content/53/12/1829.short 4100 - http://jnm.snmjournals.org/content/53/12/1829.full SO - J Nucl Med2012 Dec 01; 53 AB - 18F-FDG PET/CT allows the direct measurement of metabolic tumor burden in a variety of different malignancies. The aim of this study was to assess whether metabolic tumor volume (MTV) determined by 18F-FDG PET/CT could be used in the prediction of progression-free and overall survival in multiple myeloma patients. Methods: Forty-seven patients (18 women, 29 men; mean age ± SD, 63 ± 11 y) with stage IIIA disease who had undergone whole-body 18F-FDG PET/CT were retrospectively evaluated. Images underwent a 3-dimensional region-of-interest analysis including all focal lesions with a maximum standardized uptake value &gt; 2.5. The MTV of each lesion was calculated using an automated contouring program based on the standardized uptake value and developed with a threshold of 40% of the maximum standardized uptake value. The total MTV of each patient was defined as the sum of metabolic volume of all focal lesions. Patients were treated and then subjected to a mean follow-up period of 24 mo. Results: In the 47 patients studied, MTV range was 1.3–316.3 mL, with a median of 23.7 mL. A direct, significant correlation was found between MTV and the percentage of diffuse infiltration of bone marrow by plasma cells (r = 0.46, P = 0.006), whereas hemoglobin levels were inversely correlated with MTV (r = −0.56, P = 0.0001). At follow-up, patients who developed progressive disease (n = 18) showed a significantly higher MTV (74.7 ± 19.3 vs. 29.8 ± 5.1 mL, P = 0.009) than patients without progressive disease (n = 29). Furthermore, patients who died of myeloma (n = 9) had a significantly higher MTV (123.2 ± 30.6 vs. 28.9 ± 4.2 mL, P = 0.0001) than survivors (n = 38). No differences in age, plasma cell infiltration, M protein, albumin, β2-microglobulin, performance status, International Staging System score, and presence or absence of a bone marrow transplant were found between groups. The MTV cutoff level was determined by receiver-operating-characteristic curve analysis, and the best discriminative value found for predicting progression-free and overall survival was 42.2 and 77.6 mL, respectively. By Kaplan–Meier analysis and log-rank testing, progression-free and overall survival at follow-up were significantly better in patients showing an MTV lower than the cutoff than in those having an MTV higher than the cutoff (χ2 = 3.9, P = 0.04, and χ2 = 56.3, P &lt; 0.0001, respectively). Conclusion: The direct measurement of tumor burden obtained by calculating MTV on 18F-FDG PET/CT images may be used in the prediction of progression-free and overall survival in myeloma patients.