Objective To investigate the prognostic value of the maximum standardized uptake value(SUV_max), metabolic tumor volume(MTV) and total lesion glycolysis(TLG) calculated from pretreatment ¹⁸F-FDG PET/CT results in patients with diffuse large B-cell lymphoma of stage Ⅱ~Ⅲ disease.

Methods A total of 85 patients with DLBCL of stageⅡ~Ⅲ disease were enrolled from June 2009 to December 2015, and the clinic data and pretreatment ¹⁸F-FDG PET/CT data were retrospectively analyzed. MTV and TLG of tumor tissue were calculated from PET/CT images with the threshold value of 41% of the SUV_max. The optimal cutoff point of progression-free survival(PFS) of SUV_max, MTV and TLG were investigated by using receiver operating characteristic(ROC) curve analysis. The Kaplan-Meier method and Log-rank test were respectively used for survival analysis and univariate analysis, and COX proportional hazards model for multivariate analysis.

Results The SUV_max, MTV and TLG of 85 patients were 23.9(16.3), 25.1(95.3) cm³, 424.4(1404.6), respectively. ROC curve showed that the area under the curce(AUC) of SUV_max, MTV and TLG were 0.610, 0.729 and 0.726(95% CI: 0.483–0.736, P=0.109; 0.621–-0.838, P=0.001; 0.621–0.831, P=0.001), respectively. The median SUV_max(23.9) was used as the cutoff points due to smaller AUC of SUV_max. The cutoff point of MTV was 39.1 cm³(sensitivity=73.1% and specificity=69.5%), and the cutoff point of TLG was 404.5(sensitivity=80.8% and specificity= 61.0%). Univariate analysis showed that Ann Arbor stage, β-2 MG, lactate dehydrogenase(LDH) level, bulky disease, international prognostic index(IPI), SUV_max, MTV and TLG were relative factors affecting PFS(χ²=19.118, P=0.000; χ²=12.310, P=0.000; χ²=4.861, P=0.027; χ²=7.731, P=0.013; χ²=19.693, P=0.000; χ²=6.414, P=0.011; χ²=14.538, P=0.000; χ²=13.089, P=0.000), and Ann Arbor stage, β-2 MG, bulky disease, IPI, MTV and TLG were relative factors affecting overall survival(OS)(χ²=14.550, P=0.000; χ²=5.473, P=0.019; χ²=5.643, P=0.018; χ²=15.943, P=0.000; χ²=13.877, P=0.000; χ²=12.677, P=0.000). As MTV and TLG measures correlated strongly, only TLG measures were used for multivariate analysis. LDH level and TLG were statistically significant predictors of PFS(RR=4.891, 95%CI=1.332–11.955, P=0.017; RR=0.195, 95%CI=0.058–0.660, P=0.009), and IPI and TLG were statistically significant predictors of OS on multivariate analysis(RR=0.508, 95%CI=0.270–0.956, P=0.036; RR=0.433, 95%CI=0.227–0.826, P=0.011).

Conclusions TLG in pretreatment ¹⁸F-FDG PET/CT is an independent prognostic factor for predicting progression-free survival and overall survival time in patients with DLBCL of stageⅡ-Ⅲ disease. TLG may be more useful than SUV_max for prognosisand has certainly reference value.