Prognostic value of pretreatment (18)F-FDG PET-CT metabolic parameters in patients with advanced extranodal NK/T cell lymphoma

Abstract

Objective: To investigate the prognostic values of the maximum standardized uptake value (SUV(max)), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) calculated from pretreatment (18)F-fluorodeoxy glucose ((18)F-FDG) PET-CT results of patients with advanced extranodal NK/T cell lymphoma (ENKTL). Methods: The clinic data, follow-up data and pretreatment (18)F-FDG PET-CT data of 45 patients with ENKTL of stage Ⅳ were collected. The optimal cutoff value of progression-free survival (PFS) of SUV(max), MTV and TLG were analyzed by using receiver-operating characteristic (ROC) curve. The Kaplan-Meier method, Log-rank test and COX proportional hazards model were used for survival analysis, univariate analysis and multivariate analysis, respectively. Results: The median SUV(max), MTV and TLG of 45 ENKTL patients were 17.98, 70.18 and 755.42, respectively. ROC curve showed that the area under the curve (AUC) of SUV(max), MTV and TLG were 0.504 (P=0.970), 0.868 (P<0.001) and 0.848 (P=0.001), respectively. The value of SUV(max) was too small to fit for calculating the cutoff value of AUC. The cutoff value of MTV was 42.54 (sensitivity =78.1% and specificity =84.6%), and the cutoff value of TLG was 435.15 (sensitivity=75.0% and specificity =76.9%). Univariate analysis showed that lactate dehydrogenase (LDH) level, epstein-barr virus (EBV)-DNA, Eastern Cooperative Oncology Group (ECOG) score, bone marrow, Korean prognostic index (KPI), MTV, TLG were significantly related with PFS (all P<0.05), and lactate dehydrogenase (LDH) level, EBV-DNA, ECOG score, primary tumor location, KPI, MTV, TLG were significantly related with overall survival (OS) (all P<0.05). Multivariate analysis showed that KPI, MTV and TLG were independent prognostic predictors of PFS and OS (all P<0.05). Conclusions: MTV and TLG of pretreatment (18)F-FDG PET-CT are independent prognostic factors for PFS and OS of patients with advanced ENKTL. MTV and TLG may be more fit for evaluating the prognosis of ENKTL patients than SUV(max).