Improved survival for relapsed diffuse large B cell lymphoma is predicted by a negative pre‐transplant FDG‐PET scan following salvage chemotherapy

The utility of ([18F])fluoro-2-deoxy- d-glucose positron-emission tomography (FDG-PET) for predicting outcome after autologous stem cell transplantation (ASCT) for diffuse large B cell lymphoma (DLBCL) is uncertain - existing studies include a range of histological subtypes or have a limited duration of follow-up. Thirty-nine patients with primary-refractory or relapsed DLBCL with pre-ASCT PET scans were analysed. The median follow-up was 3 years. The 3-year progression-free survival (PFS) for patients with positive PET scans pre-ASCT was 35% vs. 81% for those who had negative PET scans (P = 0.003). The overall survival (OS) in these groups was 39% and 81% (P = 0.01), respectively. In a multivariate analysis, PET result, number of salvage cycles and the presence of relapsed or refractory disease were shown to predict a longer PFS; PET negativity (P = 0.04) was predictive of a longer OS. PET is useful for defining those with an excellent prognosis post-ASCT. Although those with positive scans can still be salvaged with current treatments, PET may useful for selecting patients eligible for novel consolidation strategies after salvage therapies.