The Value Of ¹⁸F-FDG PET Polymetabolic Parameters In The Mid-term Outcome And Prognosis Assessment Of Diffuse Large B-cell Lymphoma

Objective:Diffuse large B-cell lymphoma（DLBCL）consists of biologically heterogeneous subgroups with a variable prognosis.In recent years,although the use of rituximab（R）in addition to cyclophosphamide,doxorubicin,vincristine,and prednisone（CHOP）regimens has significantly improved patient response and survival rates,there are still patients who fail treatment and whose prognosis is poor.Therefore,early identification of patients with a poor response to treatment and a poor prognosis is essential to avoid prolonged treatment with ineffective combinations.This study assesses Interim outcomes by the ¹⁸F-fluorodeoxyglucose(¹⁸F-FDG)positron emission computed tomography/computed tomography（PET/CT）Deauville five-point scale（D-5PS）.The aim is to explore the impact of the Interim Deauville score,baseline clinical characteristics,and ¹⁸F-FDG PET/CT metabolic parameters on the prognosis of DLBCL patients,in order to provide a basis for better early prediction of patient prognosis and timely change of treatment strategy.Methods:A retrospective analysis of DLBCL patients diagnosed and treated at Taizhou people’s Hospital between January 2016 and December 2022,who underwent¹⁸F-FDG PET/CT at baseline and after 3-4 cycles of treatment of R-CHOP or R-DA-EPOCH,respectively.Retrospective analysis of ¹⁸F-FDG PET/CT performance in 31patients with DLBCL.The ¹⁸F-FDG PET/CT D-5PS was applied to assess the effect of intermediate chemotherapy,and the Fisher’s exact test was applied to analyze baseline demographic and clinical characteristics as well as baseline total metabolic tumor volume（TMTV）,total lesion glycolysis（TTLG）,baseline maximum standardized uptake value（SUVmax0）,Interim maximum standardized uptake value（SUVmax1）,change in baseline and Interim SUVmax and the rate of change（ΔSUVmax,ΔSUVmax%）correlated with efficacy;Kaplan-Meier survival analysis and Cox proportional risk model analysis were used to identify influences that were predictive of progression-free survival（PFS）in patients.Results:There were no significant differences in Interim PET outcomes between each group for clinical parameters such as gender,age at presentation（by date of pathological diagnosis）,clinical disease stage according to the Ann Arbor staging system,LDH,β2-microglobulin,number of extra-nodal organs involved,and chemotherapy regimen.There was a significant difference in Interim efficacy between each group for the Interim SUVmax1,baseline TMTV parameters,and no statistically significant difference in the remaining PET/CT parameters.Receiver operating characteristics（ROC）curve analysis showed that the best cut-off values for sensitivity and specificity of TMTV and TTLG were 142.615 cm³ and 819.36 g,respectively;the AUCs forΔSUVmax andΔSUVmax%were 0.477 and 0.427,respectively,and the AUCs for SUVmax0 and SUVmax1 were 0.618 and 0.698,respectively,with P values>0.05;only the cut-off values for TMTV and TTLG were considered to be clinically significant.Kaplan-Meier analysis showed that PFS in each group with stage I-II,TMTV<142.615 cm³,TTLG<819.39 g,and Deauville score≤3（negative）was statistically different from that in each group with stage III-IV,TMTV≥142.615 cm³,TTLG≥819.39 g and Deauville score≥4（positive）groups were compared with each other and the differences were statistically significant（p<0.05）.No significant correlation between PFS and gender,age,presence of extra-nodal lesion invasion,hematological indicators（β2-microglobulin,LDH）,or chemotherapy regimen.Multivariate analysis showed that only the Deauville score was an independent prognostic factor for PFS.PFS was shorter in patients with a positive Deauville score（score≥4）compared to those with a negative Deauville score（score≤3）（HR:4.879;95%CI:1.150-20.697;p-value:0.032）.In contrast,disease stage,TMTV,and TTLG are not independent prognostic factors.Conclusions:A positive Deauville score（score≥4）was an independent predictor for shorter PFS in patients with DLBCL receiving rituximab-containing therapy.Disease stage,TMTV,and TTLG were not independent prognostic factors.