Introduction: Fluorine-18 fluorodeoxyglucose (18 F-FDG) positron emission tomography/computed tomography (PET/CT) is a powerful tool for monitoring the response of diffuse large B-cell lymphoma (DLBCL) to therapy, but the criteria to interpret PET/CT results remain under debate. We investigated the value of post-treatment PET/CT in predicting the prognosis of DLBCL patients when interpreted according to qualitative visual trichotomous assessment (QVTA) criteria compared with the Deauville criteria.
Methods: In this retrospective study, final PET/CT scans of DLBCL patients treated with rituximab-based regimens between October 2005 and November 2010 were interpreted using the Deauville and QVTA criteria. Survival curves were estimated using Kaplan-Meier analysis and compared using the log-rank test.
Results: A total of 253 patients were enrolled. The interpretation according to the Deauville criteria revealed that 181 patients had negative PET/CT scan results and 72 had positive results. The 3 year overall survival (OS) rate was significantly higher in patients with negative scan results than in those with positive results (91.6% vs. 57.5%, P<0.001). The 72 patients with positive scan results according to the Deauville criteria were divided into two groups by the interpretation according to the QVTA criteria: 29 had indeterminate results, and 43 had positive results. The 3 year OS rate was significantly higher in patients with indeterminate scan results than in those with positive results (91.2% vs. 33.5%, P<0.001) but was similar between patients with negative and indeterminate scan results (91.6% vs. 91.2%, P=0.921).
Conclusions: Compared with the Deauville criteria, using the QVTA criteria for interpreting post-treatment PET/CT scans of DLBCL patients is likely to reduce the number of false positive results. The QVTA criteria are feasible for therapeutic outcome evaluation and can be used to guide risk-adapted therapy.