Qualitative visual trichotomous assessment improves the value of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography in predicting the prognosis of diffuse large B-cell lymphoma.

ABSTRACT

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.