Purpose: Plasmablastic lymphoma (PBL) is a rare variant of diffuse large B cell lymphomas (DLBCL) clinically characterized by a poorer prognostic. Few clinical and imaging data are available and derived from pooled case reports and small series. The aim of the study was to evaluate the FDG avidity at baseline and the utility of 18-Fluorodeoxyglucose (FDG) positron-emission-tomography/computed-tomography (PET/CT) for staging and response assessment.
Methods: Patients with newly diagnosed PBL seen at Lymphoma Study Association centers during the period 2005-2015 were included if they underwent a PET/CT at staging and at the end of treatment (eotPET) and had received an anthracycline-based first line therapy. EotPET scans were analyzed using the 5-point-scale visual analysis in accordance with Lugano criteria. Patients were classified in complete metabolic response (CMR) or no-CMR including partial metabolic response (PMR), stable disease (SD) and progression disease (PD). EotPET results were assessed for the ability to predict event free survival (EFS) and overall survival (OS).
Results: Thirty-five PBL patients fulfilled the inclusion criteria. The median follow-up was 34 months (2.8-120 months). FDG avidity was found in all patients at diagnosis. Most patients (80%) achieved CMR, and 20% were no-CMR including 9% PMR, 6% SD, and 6% PD. A CMR after first line chemotherapy predicted higher EFS (p < 0.0001) and OS (p = 0.0006).
Conclusions: This study confirmed the FDG avidity of PBL subtype and the usefulness of PET/CT scanning in restaging an aggressive lymphoma at the completion of chemotherapy. EotPET can predict outcomes following treatment in patients with PBL.
Keywords: 18-FDG-PET/CT; FDG avidity; Plasmablastic lymphoma; Post-treatment evaluation.