E5299. Global Assessment of Bone Marrow FDG Uptake to Evaluate the Efficacy of Autologous Stem Cell Transplantation
  1. Shashi Singh; Stanford University
  2. Bimash Shrestha; KIST Medical College
  3. Saira Niazi; Hospital of the University of Pennsylvania
  4. William Raynor; Rutgers Robert Wood Johnson Medical School
  5. Thomas Werner; Hospital of the University of Pennsylvania
  6. Abass Alavi; Hospital of the University of Pennsylvania
  7. Mona-Elisabeth Revheim; The Intervention Center, Rikshospitalet, Division for Technology
FDG PET/CT plays an important role in the evaluation of patients with multiple myeloma (MM) after stem cell transplantation. The aim of this study was to evaluate the efficacy of autologous stem cell transplantation (ASCT) in patients with MM using FDG PET/CT. We have hypothesized that the uptake of FDG in the bone marrow (which is a surrogate of the disease burden in bone marrow) decreases after ASCT in patients with MM.

Materials and Methods:
Retrospective FDG PET/CT data of 10 patients with MM (8 men, 2 women), aged 58.5 ± 8.01 years, who underwent ASCT were collected from the Hospital of the University of Pennsylvania. It included two scans for each patient; the first was performed before initiation of ASCT and a follow-up scan taken on average 270.3 days (range 76–605 days) after treatment. All scans were acquired 60 minutes following IV injection of 4 MBq/kg of FDG. Images were analyzed using an iterative thresholding algorithm that delineates a continuous region based on Hounsfield units from the CT data (OsiriX MD software version 12.5.2; Pixmeo SARL, Bernex, Switzerland), allowing for segmentation of the total skeleton on a fused PET/CT image. This enabled the quantification of FDG uptake representing the entire skeleton, providing a global SUVmean that considers all bone marrow involvement. Global SUVmean scores were compared before and after treatment using a two-tailed paired t-test.

The average of SUVmean before treatment was 1.23 ± 0.26 (range 0.81–1.71) compared to 1.02 ± 0.16 (range 0.77–1.26) after treatment, corresponding to an average difference of -0.21 ± 0.15 (range -0.49 to -0.04), which was statistically significant: p = 0.002.

Global assessment of the bone marrow using FDG PET/CT, as opposed to lesion-based methods of quantification, appears to be a simple and useful approach to assess the effects of ASCT in patients with MM. This study demonstrated a significant decrease in FDG uptake from baseline to posttreatment in the bone marrow of patients with MM who underwent this type of therapy. This decrease in FDG uptake in the bone marrow potentially signifies a reduction in bone marrow tumor burden following stem cell transplantation.