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.