Positive correlation between baseline PET or PET/CT findings and clinical parameters in multiple myeloma patients

Recently, positron emission tomography (PET) has been incorporated into a series of prospective studies as a predictor of outcomes in multiple myeloma (MM), and the number of ¹⁸F-fluorodeoxuglucose (FDG)-avid focal lesions (FLs) and the intensity of tumor metabolism have been designated as important surrogate markers for predicting prognosis. Here, we compared initial clinical characteristics of MM patients with baseline PET parameters: the number of FLs and the maximum standardized uptake value (SUV_max). A total of 59 patients diagnosed with MM between August 2004 and February 2012 were reviewed. At diagnosis, 23 patients (40.0%) had ≤3 FLs, 11 patients (18.6%) 4-9 FLs, and 25 patients (42.4%) ≥10 FLs. The median SUV_max was 5.3 (range 0-24.3), and 40 patients (67.8%) showed a SUV_max >4. No clinical characteristics were significantly different between groups with a SUV_max ≤4 and a SUV_max >4. However, there were significant differences in several clinical indices between the FLs ≤3 and FLs >3 groups; elevated β₂-microglobulin, elevated lactate dehydrogenase, anemia and more advanced disease by the Durie-Salmon stage corresponded to FLs >3 at baseline PET. Adverse baseline PET findings are positively correlated with prognostically relevant clinical parameters. Regarding PET parameters, FLs are more likely to be well correlated with disease aggressiveness and pathophysiology compared to SUV_max.