Prognostic Value Of Interim ¹⁸F-FDG PET/CT Metabolic Parameters In Aggressive B-cell Lymphoma

Purpose:To explore the prognostic value of multiple metabolic parameters,including maximum standardized uptake value?SUVmax?,metabolic tumor volume?MTV?,and total lesion glycolysis?TLG?,of interim ¹⁸F-fluorodeoxyglucose Positron emission tomography/Computed Tomography(¹⁸F-FDG PET/CT)in aggressive B-cell lymphoma.Methods:A retrospective analysis of 84 patients with aggressive B-cell lymphoma who were diagnosed and treated at the Lanzhou University Second Hospital from March 2016 to December 2019.All patients were confirmed by pathological diagnosis.All patients received standardized first-line chemotherapy,and¹⁸F-FDG PET/CT imaging were performed during the interim chemotherapy?during4-6 cycles?.There were 47 males and 37 females with an average age of 53.0±13.2years?16-83 years?in the study.The interim PET/CT images of all patients were analyzed using image post-processing software,and the metabolic parameters SUVmax,MTV,and TLG of all lesions were measured,and the interim PET/CT results of all patients were scored using the Deauville criteria.The clinical information was recorded,including age,B symptom,nuclcar-associated antigen Ki-67 index?Ki-67?,and Ann Arbor stage during initial diagnosis;lactate dehydrogenase?LDH?,?2-microglobulin??2-MG?,hemoglobin?Hb?during the initial diagnosis and corresponding period of PET/CT examination.According to the clinical information,all patients were scored using the International Prognostic Index?IPI?and National Comprehensive Cancer Network-International Prognostic Index?NCCN-IPI?scoring criteria.The receiver operating characteristic curve?ROC?was used to determine the optimal thresholds for the metabolic parameters—including SUVmax,MTV,and TLG—of PET/CT in prognostic evaluation of aggressive B-cell lymphoma.The correlation between SUVmax,MTV,TLG and clinical indicators was analyzed.Kaplan-Meier was used to analyze the clinical indicators,IPI score,NCCN-IPI score,PET/CT metabolic parameters,and Deauville score of patients.Log-rank test was used to compare the differences in survival curves.Cox proportional hazard regression model was used for multivariate analysis of prognostic factors.Results:1.Follow-up results:After a follow-up of 5-49 months?median follow-up of13.5 months?,3 of 84 patients died of lymphoma-related complications?3.6%?,and18 patients progressed or relapsed after treatment?21.4%?.The remaining 63 patients had no disease progression or relapse after treatment?75.0%?.The 84 patients had an average progression-free survival?PFS?period of 37.2 months,with a 1-year PFS rate of 76.5%and a 2-year PFS rate of 72.6%.2.Prognostic analysis of clinical indicators:The PFS rate was significantly lower in patients with increased LDH levels at the initial diagnosis and interim chemotherapy than those with normal LDH levels,and the difference was statistically significant??²=8.575,10.346,P=0.003,0.001?.Kaplan-Meier survival analysis showed that the LDH levels during the initial diagnosis and interim chemotherapy were the prognostic factors of aggressive B-cell lymphoma.However,the age,B symptoms,Ki-67 index,Ann Arbor stage,blood?2-MG and Hb levels were not prognostic factors.3.Prognostic analysis of IPI and NCCN-IPI scores:The incidence of adverse prognosis was significantly higher in patients with NCCN-IPI scores of 4-8 than in patients with scores of 0-3?44.4%vs 13.7%?,the difference was statistically significant?P=0.003?.However,in the IPI score,there was no statistically significant difference in the incidence of adverse prognosis between the patients with scores of0-3 and 4-5.Kaplan-Meier survival analysis showed that the NCCN-IPI score was a prognostic factor of aggressive B-cell lymphoma,while the IPI score was not a prognostic factor.4.Results of Metabolic Parameters of interim PET/CT:the interim PET/CT metabolic parameters SUVmax,MTV,and TLG in patients with poor prognosis were significantly higher than those with good prognosis,and the differences were statistically significant?all P<0.05?.Using ROC analysis,the thresholds of SUVmax,MTV,and TLG were 9.42,24.54,and 100.71,the AUC values were 0.890,0.870,and0.884,and the accuracy of the judgments were 90.5%,90.5%,and 92.9%.Patients with SUVmax,MTV,and TLG above the threshold had significantly higher incidences of adverse events than those below the threshold,and the differences were statistically significant?all P<0.05?.The patients with increased LDH levels had significantly higher SUVmax,MTV and TLG values than those with normal LDH levels.The LDH levels were significantly positively correlated with SUVmax,MTV and TLG values?r=0.408,0.493,and 0.488,all P<0.05?.Kaplan-Meier survival analysis showed that SUVmax,MTV,and TLG were all prognostic factors of aggressive B-cell lymphoma.5.Multivariate analysis results:In the Cox proportional hazard regression model,only LDH levels and SUVmax in the interim chemotherapy were independent prognostic factors for aggressive B-cell lymphoma,and the HR were 1.001 and 1.168,respectively.Other prognostic factors were not independent prognostic factors of aggressive B-cell lymphoma.Conclusion:1.In this study,interim PET/CT metabolic parameters including SUVmax,MTV,TLG and Deauville score,LDH level,NCCN-IPI score,could determine the prognosis of aggressive B-cell lymphoma.Among them,the SUVmax and LDH level were the highest prognostic ability.2.The thresholds of interim PET/CT metabolic parameters SUVmax,MTV,and TLG for the prognosis of aggressive B-cell lymphoma were 9.42,24.54,and 100.71,respectively.Patients above the threshold indicated a poor prognosis.3.The interim PET/CT metabolic parameters SUVmax,MTV,TLG values of patients with aggressive B-cell lymphoma were positively correlated with LDH levels,and have no correlation with other clinical indicators.