Brain glucose metabolism in patients with newly diagnosed multiple myeloma significantly decreases after high-dose chemotherapy followed by autologous stem cell transplantation.

The aim of this study was to compare the effect of intensive therapy [consisting of high-dose chemotherapy followed by autologous stem cell transplantation (HDC/ASCT)] and conventional standard-dose chemotherapy (CDC) on brain FDG uptake, as an indicator of glucose metabolism, in multiple myeloma patients. Twenty-four patients with newly diagnosed multiple myeloma were included. Sixteen patients received HDC/ASCT, including bortezomib-based induction therapy, and eight patients received CDC. F-fluorodeoxyglucose (FDG)-PET/computed tomography (CT) was performed 1 and 3 hours following tracer administration before and after the treatment. The manual segmentation of supratentorial and cerebellum of each patient was performed by two independent observers. The data were expressed as global mean standardized uptake values (GSUVmean). Wilcoxon signed-rank test was used to compare changes from before to after treatment. A significant decrease in the GSUVmean of supratentorial brain and cerebellum was observed after treatment in the patients who received HDC/ASCT (1 hour scans: 7.03 ± 1.18 vs. 6.56 ± 0.94; P = 0.03 and 7.01 ± 1.08 vs. 6.34 ± 0.93; P = 0.01, respectively). GSUVmean changes in the patients who received CDC were not significantly different after treatment (1 hour scans: 6.47 ± 1.16 vs. 6.21 ± 0.91; P = 0.40 and 6.30 ± 1.21 vs. 6.09 ± 0.86; P = 0.62, respectively). The same findings were observed for 3 hours scans. A high level of agreement was observed between two operators. Multiple myeloma patients who received HDC/ASCT demonstrated a significant decrease in FDG uptake in the supratentorial brain and cerebellum, while patients who received CDC did not demonstrate significant changes in the brain FDG uptake.