| Part1:Prognostic value of 18F-FDG PET/CT imaging and related factors for lymphoma patients before or after hematopoietic stem cell transplantationPurpose:In the present study,we mainly aimed to evaluate the prognostic value of 2deoxy-2-[18F]fluoro-D-glucose(18F-FDG)positron emission tomography(PET)/computed tomography(CT)and related factors before or after stem cell transplantation(HSCT)in lymphoma.Methods:From Jan 2010 and December 2020,all patients who underwent autologous(auto-)and allogeneic(allo-)HSCT for lymphoma and had pre-or post-transplantation 18FFDG PET/CT in our institution were respectively included.These above-mentioned patients were divided into positive group(DS≥4)and negative group(DS<4)based on the Deauville criteria.Characteristics considered were age,gender,type of lymphoma,Ann Arbor stage,lactate dehydrogenase(LDH),previous lines of treatment,Eastern Cooperative Oncology Group performance status(ECOG PS),extranodal lesions,conditioning regimen,disease status at transplantation,donor type,and PET/CT results before or after transplantation.Overall survival(OS)was defined as the time from day 0 of allo-SCT to death or last followup for survivors.Progression-free survival(PFS)was defined as the time from day 0 of alloSCT to the date of progression/relapse,death,or last follow-up without evidence of relapse or disease progression.Kaplan-Meier method was used in survival analysis,and the log-rank method was adopted in comparison.Prognostic factor analysis was performed by the Cox regression model.Results:245 patients were identified,132 with auto-and 113 with allo-HSCT.(1)3year PFS rate and OS rate of lymphoma patients underwent auto-HSCT is 64.7%and 84.7%,respectively.significant differences of PFS rate were found between patients with ECOG<1 group and ECOG≥2,between patients with LDH≤upper laboratory limit(ULN)and LDH>ULN,between patients with negative and positive pre-transplant 18F-FDG PET/CT results,and between patients with negative and positive post-transplant 18F-FDG PET/CT results(all of above P<0.05).Significant differences of OS rate were found between patients with ECOG<1 group and ECOG>2,between male and female patients,and between patients with negative and positive post-transplant 18F-FDG PET/CT results(all of above P<0.05).Multivariate analysis showed that the risk of progression in patients with positive pretransplant PET results,positive post-transplant PET results and LDH>ULN was significantly higher than those with negative pre-or post-transplant PET results and LDH≤ULN[HR=3.915(95%CI:1.153-13.300),HR=4.797(95%CI:1.560-14.751),HR=4.500(95%CI:1.345-15.058),respectively].And the risk of death in patients with positive post-transplant PET results was significantly higher than those with negative results[HR=4.793(95%CI:1.268-18.124)].Besides,the combination of pre-and posttransplant PET and LDH was statistically significant for predicting PFS and OS[(χ2=38.030,P=0.000)and(χ2=12.252,P=0.002),respectively].(2)3-year PFS rate and OS rate of lymphoma patients underwent allo-HSCT is 57.7%and 71.0%,respectively.Significant differences of PFS rate were found between male and female patients,between patients under 40-year-old and over 40-year-old,between patients with LDH≤ULN and LDH>ULN,between patients with number of previous treatments=1 and number of previous treatments≥2,and between patients with negative and positive post-transplant 18F-FDG PET/CT results(all of above P<0.05).Significant differences of OS rate were found between NHL and HL patients,between different donor type groups,between patients with LDH≤ULN and LDH>ULN,and between patients with negative and positive post-transplant 18F-FDG PET/CT results(all of above P<0.05).Multivariate analysis showed that the risk of progression in patients with female gender,HL,LDH>ULN,positive post-transplant PET results was significantly higher than those with male gender,B cell and T cell NHL,LDH≤ULN,and negative post-transplant PET results[HR=3.297(95%CI:1.618-6.719),HR=23.578(95%CI:5.116-108.656)and HR=11.325(95%CI:2.961-43.313),HR=3.046(95%CI:1.450-6.398),HR=5.389(95%CI:2.781-10.444),respectively].And the risk of death in patients with HL,LDH>ULN,positive post-transplant PET results and HLA haploidentical and identical sibling donors was significantly higher than those with B cell and T cell NHL,LDH≤ULN,negative post-transplant PET results and Unrelated donors[.HR=37.164(95%CI:6.532-211.445)and HR=33.958(95%CI:6.725-171.463),HR=3.922(95%CI:1.360-11.313),[HR=2.977(95%CI:1.183-7.491),HR=9.831(95%CI:1.232-78.434)and HR=18.117(95%CI:2.088-157.205)].Besides,the combination of pre-and post-transplant PET and LDH was statistically significant for predicting PFS and OS(P<0.05).Conclusions:Collectively,we found that 18F-FDG PET/CT imaging before autoHSCT was a strong indicator for PFS,and 18F-FDG PET/CT imaging after HSCT(including autologous and allogeneic)was a strong indicator for both PFS and OS.The combination of pre-and post-transplant PET and LDH may add extra benefit for prognostic evaluation.Part2:A preliminary study on the prognostic value of post-transplant 18F-FDG PET/CT imaging in patients with lymphoma at different time WindowsPurpose:In the present study,we mainly aimed to evaluate the prognostic value of post-transplant 18F-FDG PET/CT imaging in patients with lymphoma at different time Windows.Methods:From Jan 2010 and December 2020,All patients who underwent auto-and allo-HSCT for lymphoma and had post-transplantation 18F-FDG PET/CT(within 6 months after auto-HSCT or 12 months after allo-HSCT)in our institution were respectively included.According to the timing of post-transplant PET examination,patients underwent auto-HSCT were divided into within 3 months group and within 3-6 months group while patients underwent allo-HSCT were divided into within 3 months group,within 3-6 months group,and within 6-12 months group.Patients who underwent 2 or more 18F-FDG PET/CT imaging within 12 months after allo-HSCT were also screened.Progression-free survival(PFS)and overall survival(OS)were recorded.Kaplan-Meier method was used in survival analysis,and the log-rank method was adopted in comparison.Results:(1)For patients who had 18F-FDG PET/CT scan within 3-6 months after autoHSCT,3-year PFS and OS of the negative PET/CT group and positive PET/CT group was 59.5%versus 42.9%(χ2=4.855,P=0.028)and 86.1%versus 67.7%(χ2=3.927,P=0.048).However,among patients who had 18F-FDG PET/CT scan within 3months after auto-HSCT,there was no significant difference in PFS and OS between the negative PET/CT group and positive PET/CT group(P>0.05).(2)Among patients who had 18F-FDG PET/CT scan within 3months after allo-HSCT,3-year PFS and OS of the negative PET/CT group and positive PET/CT group was 59.8%versus 42.9%(χ2=2.564,P=0.109)and 71.9%versus 42.9%(χ2=5.460,P=0.019).Among patients who had 18F-FDG PET/CT scan within 3-6 months after allo-HSCT,3-year PFS and OS of the negative PET/CT group and positive PET/CT group was 69.7%versus 11.1%(χ2=20.619,P=0.000)and 70.5%versus 46.7%(x2=5.542,P=0.019).Among patients who had 18F-FDG PET/CT scan within 6-12 months after alloHSCT,3-year PFS and OS of the negative PET/CT group and positive PET/CT group was 73.4%versus 25.0%(χ2=9.773,P=0.002)and 88.9%versus 85.7%(χ2=0.086,P=0.769).(3)Based on 2 or more 18F-FDG PET/CT imaging within 12 months after allo-HSCT,it is speculated that false positives are more likely to occur in early 18F-FDG PET/CT imaging after allo-HSCT.Serial imaging after allo-HSCT facilitated early diagnosis of recurrence/progression in patients with lymphoma and could improve the specificity of 18FFDG PET/CT imaging results after transplantation.Conclusions:A time window of 3-6 months might be appropriate for post-transplant(including autologous and allogeneic)18F-FDG PET/CT.Serial imaging after allo-HSCT could help to identify false positives and early diagnosis of recurrence/progression in patients with lymphoma.Part3:Analysis of positive 18F-FDG PET/CT imaging results after hematopoietic stem cell transplantation for lymphoma patientsPurpose:In the present study,it is intended to optimize the interpretation of posttransplant 18F-FDG PET/CT results by analyzing the positive results of 18F-FDG PET/CT imaging after allo-HSCT.Methods:From Jan 2010 and December 2020,all patients who underwent autologous(auto-)and allogeneic(allo-)HSCT for lymphoma and had pre-or post-transplantation 18FFDG PET/CT in our institution were respectively included.These above-mentioned patients were divided into positive group(DS>4)and negative group(DS<4)based on the Deauville criteria,and of whom target lesions were analyzed on the integrated CT according to the CTBased Response on the Lugano Classification.18F-FDG PET/CT results were compared with the results from pathological examination,clinical long-term follow-up(≥6 months)and conventional imaging.Diagnostic efficiency of 18F-FDG PET/CT and integrated CT in detecting lymphoma were calculated.IBM SPSS Statistics(Version 26.0)was used for all statistical analyses.Consistencies were evaluated by comparing 18F-FDG PET/CT and integrated CT results through kappa coefficient.Results:(1)The sensitivity,specificity,positive predictive value,negative predictive value,accuracy of 18F-FDG PET/CT after auto-HSCT and allo-HSCT were 100%(17/17).76.3%(61/80)、47.2%(17/36)、100%(61/61)、86.7%(78/97)and 100%(17/17).92.6%(87/94)、70.8%(17/24)、100%(87/87)、93.7%(104/111),respectively.(2)18F-FDG PET/CT imaging after auto-HSCT showed that patients with FDG-avid lymph nodes in a single region or single FDG-avid extranodal lesion had a higher possibility of false positive compared with Multiple FDG-avid lesions(P=0.002).But there was no statistically significant difference among patients underwent Allo-HSCT(P=0.356).(3)It was more likely for new FDG-avid nodes outside regions of previous disease after autoHSCT and allo-HSCT to be false positives(P=0.000 and P=0.009,respectively).(4)It was more likely that the false positive rate of 18F-FDG PET/CT scan within 3 months after HSCT was higher than that within 3-12 months,including auto-HSCT and allo-HSCT,but the difference was not statistically significant(P>0.05).(5)Patients with a DS score of 5 on 18FFDG PET/CT imaging after transplantation were more likely to have lymphoma involvement than those with a DS score of 4(P=0.004).However,in the subgroup with extranodal lesion involvement,a score of 4 or 5 should be considered lymphoma involvement.(6)The consistency of 18F-FDG PET/CT and integrated CT after auto-HSCT and allo-HSCT was poor(Kappa=0.391,P<0.001)and moderate(Kappa=0.660,P<0.001).When 18F-FDG PET/CT imaging showed the suggestive foci were in lymph nodes only,FDG-avid lymph nodes>1.5 cm on CT were more likely to be lymphoma involvement(P<0.001).Conclusions:Post-transplant 18F-FDG PET/CT had a high sensitivity to detect lymphoma involved lesions,but also a high false positive rate.Some specific imaging features may help improve the interpretation of post-transplant 18F-FDG PET/CT results. |
