***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: PET using 18F-FDG has prognostic value when performed at the completion of initial chemotherapy in patients with diffuse large B-cell lymphoma ( DLBCL ) . 18F-FDG PET may also be predictive of outcome when performed during the treatment course of DLBCL , but robust prospect i ve studies and st and ardization of 18F-FDG PET interpretation in this setting are lacking . Methods : In this prospect i ve study , patients with advanced-stage DLBCL were treated with st and ard rituximab , cyclophosphamide , doxorubicin , vincristine , and prednisone chemotherapy , and 18F-FDG PET/CT was performed after cycle 2 or 3 and at the end of therapy . The 18F-FDG PET/CT scans were interpreted according to the International Harmonization Project for Response Criteria in Lymphoma , and the maximum st and ardized uptake value ( SUV ) of the most 18F-FDG – avid lesions was recorded . Results : Fifty patients were enrolled , and all underwent interim 18F-FDG PET/CT . At a median follow-up of 33.9 mo , the positive predictive value ( PPV ) of interim 18F-FDG PET/CT for relapse or progression was 42 % , and the negative predictive value ( NPV ) was 77 % . Interim 18F-FDG PET/CT was significantly associated with event-free survival ( P = 0.017 ) and with progression-free survival ( P = 0.04 ) but not with overall survival ( P = 0.08 ) . End-of-therapy 18F-FDG PET/CT had high PPV and NPV ( 71 % and 80 % , respectively ) and was significantly associated with event-free survival , progression-free survival , and overall survival ( P < 0.001 ) . SUV measurements did not discriminate patients who relapsed or progressed from those who remained in remission . Conclusion : When performed after 2 cycles of immunochemotherapy and interpreted according to International Harmonization Project criteria , early response assessment with PET/CT has a high NPV but low PPV in patients with advanced-stage DLBCL . Prospect i ve trials are required to vali date different criteria for the interpretation of interim 18F-FDG PET/CT and establish the role of interim 18F-FDG PET/CT in the management of patients with DLBCL The International Prognostic Index ( IPI ) is a widely accepted model that is used to predict the prognosis of patients with diffuse large B-cell lymphoma ( DLBCL ) who are treated using chemotherapy .  However , the prognostic value of the IPI has been a focal point of debate in the immunochemotherapy era . The aim of this study was to reassess the value of the IPI and revised IPI ( R-IPI ) in a Chinese population . A multicentre retrospective analysis of DLBCL patients who were treated with cyclophosphamide , doxorubicin , vincristine and prednisone (CHOP)-like chemotherapy alone or chemotherapy plus rituximab ( R-CHOP-like ) was performed . The prognostic values of IPI and R-IPI at the time of diagnosis with respect to overall survival ( OS ) and progression-free survival ( PFS ) were evaluated . Among the 438 patients in the study , 241 received a CHOP-like regimen and 197 patients received an R-CHOP-like regimen . Although the IPI remained predictive for the CHOP-like group , it failed to distinguish between the various prognostic categories in the R-CHOP-like group . Notably , redistribution of the IPI factors into R-IPI factors identified three discrete prognostic groups with significantly different outcomes in both the CHOP-like and R-CHOP-like groups . In the R-CHOP-like group , these three risk groups , very good , good and poor , had distinctly different 3-year PFS rates of 96 , 84.3 and 67.5 % ( P=0.001 ) , and 3-year OS rates of 96 , 87.6 and 71.1 % ( P=0.003 ) , respectively . Our study demonstrates the power of the R-IPI as a simplified and more clinical ly relevant predictor of disease outcome than the st and ard IPI in DLBCL population s in the rituximab era . Therefore , the R-IPI merits further study in a larger population -based prospect i ve study The prognostic value of interim positron emission tomography ( PET ) interpreted according to visual criteria is a matter of debate in diffuse large B-cell lymphoma ( DLBCL ) . Maximal st and ardized uptake value reduction ( ΔSUVmax ) may better predict outcome . To compare the prognostic value of both methods , we analyzed PET done at baseline ( PET0 ) and after 2 ( PET2 ) and 4 ( PET4 ) cycles in 85 patients with high-risk DLBCL enrolled on a prospect i ve multicenter trial . All images were central ly review ed and interpreted visually according to the International Harmonization Project criteria and by computing ΔSUVmax between PET0 and PET2 ( ΔSUVmaxPET0 - 2 ) or PET4 ( ΔSUVmaxPET0 - 4 ) . Optimal cutoff to predict progression or death was 66 % for ΔSUVmaxPET0 - 2 and 70 % for ΔSUVmaxPET0 - 4 . Outcomes did not differ significantly whether PET2 and PET4 were visually positive or negative . Inversely , ΔSUVmaxPET0 - 2 analysis ( > 66 % vs ≤ 66 % ) identified patients with significantly different 2-year progression-free survival ( 77 % vs 57 % ; P = .0282 ) and overall survival ( 93 % vs 60 % ; P < .0001 ) . ΔSUVmaxPET0 - 4 analysis ( > 70 % vs ≤ 70 % ) seemed even more predictive for 2-year progression-free survival ( 83 vs 40 % ; P < .0001 ) and overall survival ( 94 % vs 50 % ; P < .0001 ) . ΔSUVmax analysis of sequential interim PET is feasible for high-risk DLBCL and better predicts outcome than visual analysis . The trial was registered at http:// clinical trials.gov as NCT00498043 BACKGROUND Revised response criteria for aggressive lymphomas have been proposed ( Cheson , J Clin Oncol , 2007 ) stressing the role of (18)fluorodeoxyglucose-positron emission tomography ( PET ) in posttreatment evaluation . The value of PET after four cycles compared with the International Workshop Criteria ( IWC ) remains to be established . PATIENTS AND METHODS In all , 103 patients with untreated diffuse large B-cell lymphoma were prospect ively enrolled to evaluate the prognostic impact of PET after two and four cycles . RESULTS Median age was 53 years ( 19 - 79 ) , 68 % male . The International Prognostic Index was low=22 % , low-intermediate=19 % , intermediate-high=33 % and high risk=26 % . Treatment consisted of cyclophosphamide , doxorubicin , vincristine , prednisone ( CHOP ) ( 30 % ) or dose-intensified CHOP ( 70 % ) , with rituximab ( 49 % ) or without ( 51 % ) . Ninety-nine patients were evaluated by PET and IWC at four cycles : 77 ( 78 % ) had a negative PET , while 22 ( 22 % ) remained positive . The 5-year event-free survival ( EFS ) was 36 % for patients with a positive PET versus 80 % with a negative examination , whatever the response [ complete response ( CR ) versus partial response ( PR ) ] according to IWC ( P<0.0001 ) . Positive PET patients had a 5-year EFS of 58 % if in CR/CR unconfirmed by IWC and 0 % if not ( P<0.0001 ) . The same observations could be made in patients treated with and without rituximab . CONCLUSION The integration of PET in treatment evaluation offers a powerful tool to predict outcome PURPOSE (18)F-fluoro-2-dexoy-D-glucose-positron emission tomography (FDG-PET)/computerised tomography ( CT ) has been used for staging and monitoring responses to treatment in patients with diffuse large B cell lymphoma ( DLBCL ) . The sequential interim PET/CT was prospect ively investigated to determine whether it provided additional prognostic information and could be a positive predictable value within patients with the same international prognostic index ( IPI ) after the use of rituximab in DLBCL . METHODS One hundred and sixty-one patients with newly diagnosed DLBCL were enroled ; the assessment of the PET/CT was performed at the time of diagnosis and mid-treatment of rituxibmab , cyclophosphamide , doxorubicin , vincristine and prednisolone ( R-CHOP ) . RESULTS Sixty-seven patients ( 41.6 % ) presented with advanced stage disease and 27 ( 16.8 % ) had bulky lesions . Forty-three patients ( 26.7 % ) continued to have positive metabolic uptakes with a significantly high relapse rate ( 62.8 % ) compared to the patients with a negative interim PET/CT ( 12.1 % ) ( P<0.01 ) . After a median follow-up of 30.8months , the positivity of interim PET/CT was found to be a prognostic factor for both overall survival ( OS ) and progression-free survival ( PFS ) , with a hazard ratio of 4.07 ( 2.62 - 6.32 ) and 5.46 ( 3.49 - 8.52 ) , respectively . In the low-risk IPI group , the 3-year OS and PFS rates were significantly different in the patients with positive ( 53.3 % and 52.5 % ) and negative ( 93.8 % and 88.3 % ) interim PET/CT , respectively ( P<0.01 ) . These significant prognostic differences of interim PET/CT responses were consistent with the results of the patients with high-risk IPI group ( P<0.01 ) . CONCLUSIONS Interim PET/CT scanning had a significant predictive value for disease progression and survival of DLBCL in post-rituximab treatment ; it might be the single most important determinant of clinical outcome in patients with the same IPI risk PURPOSE Our main objective was to prospect ively determine the prognostic value of [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography ( PET/CT ) after two cycles of rituximab plus cyclophosphamide , doxorubicin , vincristine , and prednisone given every 14 days ( R-CHOP-14 ) under st and ardized treatment and PET evaluation criteria . PATIENTS AND METHODS Patients with any stage of diffuse large B-cell lymphoma were treated with six cycles of R-CHOP-14 followed by two cycles of rituximab . PET/CT examinations were performed at baseline , after two cycles ( and after four cycles if the patient was PET-positive after two cycles ) , and at the end of treatment . PET/CT examinations were evaluated locally and by central review . The primary end point was event-free survival at 2 years ( 2-year EFS ) . RESULTS Median age of the 138 evaluable patients was 58.5 years with a WHO performance status of 0 , 1 , or 2 in 56 % , 36 % , or 8 % of the patients , respectively . By local assessment , 83 PET/CT scans ( 60 % ) were reported as positive and 55 ( 40 % ) as negative after two cycles of R-CHOP-14 . Two-year EFS was significantly shorter for PET-positive compared with PET-negative patients ( 48 % v 74 % ; P = .004 ) . Overall survival at 2 years was not significantly different , with 88 % for PET-positive versus 91 % for PET-negative patients ( P = .46 ) . By using central review and the Deauville criteria , 2-year EFS was 41 % versus 76 % ( P < .001 ) for patients who had interim PET/CT scans after two cycles of R-CHOP-14 and 24 % versus 72 % ( P < .001 ) for patients who had PET/CT scans at the end of treatment . CONCLUSION Our results confirmed that an interim PET/CT scan has limited prognostic value in patients with diffuse large B-cell lymphoma homogeneously treated with six cycles of R-CHOP-14 in a large prospect i ve trial . At this point , interim PET/CT scanning is not ready for clinical use to guide treatment decisions in individual patients Positron emission tomography ( PET ) has been found useful in monitoring response to treatment of malignant lymphoma . We investigated the ability of interim PET to monitor response to st and ard dose R-CHOP chemotherapy in chemotherapy-naïve patients with diffuse large B-cell lymphoma ( DLBCL ) . Between March 2004 and April 2009 , 155 DLBCL patients treated with R-CHOP and available for interim and post-treatment PET/CT were identified and included in this analysis .  Response , 
    Output:
    
In subgroup analysis , IHP , Deauville criteria , and having no st and ard interpretation groups were factors able to predict PFS ; IHP and having no st and ard interpretation group were able to predict OS .
No significant difference in OS was observed when patients received 3 or fewer cycles of chemotherapy before PET/CT , though OS was significantly lower in patients receiving more than 3 chemotherapy cycles .
Conclusion IHP and Deauville criteria are commonly used for PET/CT visual evaluation at present .
Interim PET/CT analysis after 3 - 4 chemotherapy cycles is capable of predicting disease prognosis .