(18)F-deoxyglucose PET: useful in the management of patients with stem cell transplantation for lymphoma?

(18)F-deoxyglucose (FDG) positron emission tomography (PET) and more recently FDG PET/computed tomography (CT) has become an important tool in the management of patients with Hodgkin and non-Hodgkin lymphoma. It adds metabolic and functional information to conventional anatomical imaging, mainly assessed by CT. Especially for the detection of early response to treatment and prognostic considerations, this type of information seems better suited than anatomical information. Consequently, the ability of FDG PET to predict the outcome in patients with stem cell transplantation (SCT) for lymphoma has been tested in several studies. Results in patients with autologous SCT have been promising, and pretransplant FDG PET is likely to become routine in this group of patients. The evaluated study investigates, for the first time, the predictive value of pretransplant FDG PET in allogeneic SCT, as well as the utility of FDG PET for the follow-up of these patients. All 80 patients included in the prospective study had reduced-intensity conditioning. In contrast to FDG PET before autologous SCT, there was no correlation at all between pretransplant FDG PET results and the outcome after allogeneic SCT. This reflects the fact that other or additional reasons, especially the graft-versus-leukemia effect, are substantial for the outcome of allogeneic SCT in comparison with autologous SCT. Follow-up with FDG PET after reduced-intensity allogeneic SCT was significantly more sensitive than CT to detect disease progression or relapse, and was useful in guiding treatment in the situation of disease relapse.