Prognostic Value Of Interim PET/CT Based On Visual And Semi-Quantitative Analysis In Patients With Diffuse Large B Cell Lymphoma

?Purpose?The role of interim 18 F-fluorodeoxyglucose positron emission tomography/computed tomography(iPET/CT)in diffuse large B cell lymphoma(DLBCL)remains controversy.The purpose of this study was to assess the prognostic value of iPET/CT in patients with newly diagnosed with DLBCL according to visual and semi-quantitative interpreting methods.?Methods?129 newly diagnosed DLBCL patients with baseline PET/CT were retrospectively screened.The patients treated with CHOP ± R and underwent the iPET/CT after two or four cycles of chemotherapy were finally enrolled.The iPET/CT was evaluated by Deauville 5-point scale(DS)and ?SUVmax.Furthermore,the reduction of SUVmax incorporated with tumor size(?SUVmax*?SLD)was calculated.Sensitivity,specificity,and accuracy were calculated for each iPET/CT interpreting method.The optimal cutoff values of ?SUVmax and?SUVmax*?SLD were determined by receiver operating characteristic(ROC)analysis,respectively.Kaplan–Meier analysis was applied to test for the influence of prognostic values.Univariate and multivariate Cox proportional hazards analyses of clinical characteristics(gender,IPI score,Bone marrow involvement)and three interpreting methods were performed to examine the potential independent impacts of iPET/CT and clinical variables on PFS and OS.?Results?Seventy-seven patients with iPET/CT performed after 4 cycles of chemotherapy were finally enrolled.The optimal cutoff values for ?SUVmax and ?SUVmax*?SLD were 75%and 30%,respectively.After a median follow-up of 23 months,iPET/CT were significant predictors of PFS and OS,whenever iPET/CT was interpreted by DS,?SUVmax,or?SUVmax*?SLD method.?SUVmax-based methods were more accurate than DS.The IPI,DS,?SUVmax,and ?SUVmax*?SLD were predictive in univariate analysis.However,in multivariate analysis,only IPI and ?SUVmax remained independent predictors of PFS and OS.?Conclusions?Interim PET/CT could help to identify DLBCL patients with different prognosis.The?SUVmax analysis shows the best accuracy and the strongest predictive value among these three methods.?SUVmax*?SLD could be a promising parameter to interpret iPET/CT.Further randomized larger and prospective studies are warranted to confirm these results.