Chemokine receptor-4 targeted PET/CT with 68Ga-Pentixafor in assessment of newly diagnosed multiple myeloma: comparison to 18F-FDG PET/CT

Purpose F-18-FDG PET/CT has some limitations in the evaluation of multiple myeloma (MM). Since chemokine receptor-4 is overexpressed in MM, we perform a prospective cohort study to compare the performance of Ga-68-Pentixafor and F-18-FDG PET/CT in newly diagnosed MM. Methods Thirty patients with newly diagnosed MM were recruited. All patients underwent Ga-68-Pentixafor and(18)F-FDG PET/CT within 1 week after enrollment. A positive PET/CT was defined as the presence of focal PET-positive lesions in bone marrow or diffuse bone marrow patterns (uptake > liver). Bone marrow uptake values in Ga-68-Pentixafor and(18)F-FDG PET/CT (total bone marrow glycolysis [TBmG(FDG)], total bone marrow uptake with Ga-68-Pentixafor [TBmU(CXCR4)], total bone marrow volume [TBmV], SUVmean, and SUVmax) were obtained by drawing total bone marrow volume of interest on PET/CT. The positive rates of the PET/CT scans were statistically compared, and the correlation between quantitative bone marrow uptake values and clinical characteristics, laboratory findings, and staging was analyzed. Results Ga-68-Pentixafor PET/CT had a higher positive rate than F-18-FDG PET/CT in recruited patients (93.3 vs. 53.3%, p = 0.0005). In quantitative analysis, bone marrow uptake values in Ga-68-Pentixafor (TBmU(CXCR4), SUVmax, and SUVmean) were positively correlated with end organ damage, staging, and laboratory biomarkers related to tumor burden including serum beta 2-microglobulin, serum free light chain, and 24-h urine light chain (p < 0.05). In F-18-FDG PET/CT, only the SUVmean of total bone marrow was positively correlated with serum free light chain and 24-h urine light chain (p < 0.05). Conclusions Ga-68-Pentixafor PET/CT is promising in assessment of newly diagnosed MM.