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 pre-ASCT PET images, obtaining post-ASCT PET images does not seem to be mandatory.