The Deauville 5-Point Scale Improves the Prognostic Value of Interim FDG PET/CT in Extranodal Natural Killer/T-Cell Lymphoma

Purpose The prognostic value of FDG PET/CT in extranodal natural killer/T-cell lymphoma (ENKTL) is still controversial. Furthermore, the utility of the Deauville 5-point scale (DS) in ENKTL is uncertain. Therefore, we designed a prospective study to examine the prognostic value of 3 methods of PET/CT analysis (International Harmonization Project [IHP] criteria, DS, and SUV-based assessment). Patients and Methods Sixty patients with newly diagnosed untreated ENKTL were enrolled. PET/CT evaluation was performed before initial treatment (pretreatment) and midtreatment (interim). Interim PET/CT response was determined based on IHP criteria, DS, and change in FDG uptake (Delta SUVmax). International Harmonization Project criteria, DS, and Delta SUVmax were then examined for the ability to predict progression-free survival (PFS) and overall survival (OS). Results Over a median follow-up of 23.5 months, interim PET/CT based on DS and Delta SUVmax were significant predictors of PFS and OS. After multivariate analysis, DS was an independent predictor of PFS (P < 0.001) and OS (P < 0.001). Delta SUVmax was an independent predictor of OS (P = 0.013) but not PFS (P = 0.054) and with a lower accuracy and positive predictive value than DS. Conclusions Interim PET/CT analysis with DS predicts unfavorable treatment outcomes of ENKTL patients, whereas interim PET/CT analysis based on IHP criteria and SUV-based assessment have limited prognostic value.