The impact of pre- and post-transplantation positron emission tomography using 18-fluorodeoxyglucose on poor-prognosis lymphoma patients undergoing autologous stem cell transplantation

BACKGROUND. In patients with lymphoma who had a poor prognosis, pretransplantation 18-fluorodeoxyglucose (FDG)-positron-emission tomography (PET) was important for the evaluation of response and outcome. However, little is known about the correlation of FDG-PET with post-transplantation PET The current study was designed to ascertain whether positive pretransplantation PET images are modified by the conditioning regimen. METHODS. Sixty consecutive patients who had achieved remission and underwent consolidation by autologous stem cell transplantation (ASCT) had PET images obtained before ASCT (after 3 or 4 chemotherapy cycles) and 100 days after ASCT. The correlation was explored between the presence of abnormal 18-FDG uptake (PET positive) or its absence (PET negative) and patient outcomes. RESULTS. Before ASCT, 31 patients achieved complete remission (CR), and 23 patients achieved uncertain CR. Before ASCT, 44 patients (75%) were had negative PET images; and, after ASCT, 48 patients (80%) had negative PET images. One year after ASCT, the estimated event-free survival (EFS) rate was 80% in patients who had negative pre-ASCT PET images compared with 43% in patients who had positive pre-ASCT PET images (P =.0002). The EFS rate was 81% in patients who had negative post-ASCT PET images compared with 25% in patients who had negative post-ASCT PET images (P <.0001). In multivariate analysis, only the results for pre- and post-ASCT PET images retained prognostic value, with relative risks of failure estimated at 4.9 and 11.9, respectively. CONCLUSIONS. A positive pre-ASCT PET image indicated a high risk of ASCT failure, which was increased by a positive post-ASCT PET image. For patients with lymphoma who have positive pre-ASCT PET images, more investigations using new treatment approaches will be required. For patients who have negative preASCT PET images, obtaining post-ASCT PET images does not seem to be mandatory.