***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: PURPOSE The International Prognostic Index ( IPI ) is widely used for risk stratification of patients with aggressive B-cell lymphoma . The introduction of rituximab has markedly improved outcome , and R-CHOP ( rituximab + cyclophosphamide , doxorubicin , vincristine , prednisone ) has become the st and ard treatment for CD20(+ ) diffuse large B-cell lymphoma . To investigate whether the IPI has maintained its power for risk stratification when rituximab is combined with CHOP , we analyzed the prognostic relevance of IPI in three prospect i ve clinical trials . PATIENTS AND METHODS In total , 1,062 patients treated with rituximab were included ( MabThera International Trial [ MInT ] , 380 patients ; dose-escalated regimen of cyclophosphamide , doxorubicin , vincristine , etoposide , and prednisone ( MegaCHOEP ) trial , 72 patients ; CHOP + rituximab for patients older than age 60 years [ RICOVER-60 ] trial , 610 patients ) . A multivariate proportional hazards modeling was performed for single IPI factors under rituximab on event-free , progression-free , and overall survival . RESULTS IPI score was significant for all three end points . Rituximab significantly improved treatment outcome within each IPI group result ing in a quenching of the Kaplan-Meier estimators . However , IPI was a significant prognostic factor in all three end points and the ordering of the IPI groups remained valid . The relative risk estimates of single IPI factors and their order in patients treated with R-CHOP were similar to those found with CHOP . CONCLUSION The effects of rituximab were superimposed on the effects of CHOP with no interactions between chemotherapy and antibody therapy . These results demonstrate that the IPI is still valid in the R-CHOP era The purpose of this study was to assess the prognostic value of early 18F-FDG PET using st and ardized uptake value ( SUV ) compared with visual analysis in patients with diffuse large B-cell lymphoma ( DLBCL ) . Methods : Ninety-two patients with newly diagnosed DLBCL underwent 18F-FDG PET prospect ively before and after 2 cycles of chemotherapy ( at midtherapy ) . Maximum SUV ( SUVmax ) and mean SUV ( SUVmean ) normalized to body weight and body surface area , as well as tumor-to-normal ratios , were computed on the most intense uptake areas . The SUVs , tumor-to-normal ratios , and their changes over time were compared with visual analysis for predicting event-free survival ( EFS ) and overall survival , using receiver-operating-characteristic ( ROC ) analysis . Survival curves were estimated with Kaplan – Meier analysis and compared using the log-rank test . Results : With visual analysis , the accuracy of early PET to predict EFS was 65.2 % . The 2-y estimate for EFS was 51 % ( 95 % confidence interval [ CI ] , 34%–68 % ) in the PET-positive group compared with 79 % ( 95 % CI , 68%–90 % ) in the PET-negative group ( P = 0.009 ) . An optimal cutoff value of 65.7 % SUVmax reduction from baseline to midtherapy obtained from ROC analysis yielded an accuracy of 76.1 % to predict EFS . The 2-y estimate for EFS was 21 % ( 95 % CI , 0%–42 % ) in patients with SUVmax reduction ≤ 65.7 % compared with 79 % ( 95 % CI , 69%–88 % ) in those with reduction > 65.7 % ( P < 0.0001 ) . Fourteen patients considered as positive on visual analysis could have been reclassified as good responders . Conclusion : SUV-based assessment of therapeutic response during first-line chemotherapy improves the prognostic value of early 18F-FDG PET compared with visual analysis in DLBCL 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 Objective The aim of this study was to analyze the prognostic value of the interim PET (iPET)-computed tomography ( CT ) ( iPET-CT ) after two cycles of immunochemotherapy with the R-CHOP protocol in patients with diffuse large B-cell non-Hodgkin lymphoma ( DLBCL ) treated with a curative intent in combination with the neoplastic cell origin defined by Hans ’s immunohistochemstry algorithm followed in a reference center for cancer treatment in Brazil . Material s and methods We prospect ively evaluated 147 DLBCL patients treated with R-CHOP-21  to assess the value of the International Prognostic Index , iPET-CT , and cell of origin by immunohistochemistry as prognostic markers in the rituximab era . Fluorine-18 fluorodeoxyglucose PET-CT was performed after two cycles ( iPET-CT ) and at the end of treatment in 111 patients . Lymphoma cases were categorized into germinal center ( GC ) and nongerminal center subtypes by immunohistochemistry according to Hans ’s algorithm . Results The median age of GC-DLBCL patients ( 52.7 years ) was lower than that of nongerminal center-DLBCL patients ( 59.4 years ) ( P=0.021 ) ; in addition , it was lower in patients with negative iPET-CT findings ( 52.7 years ) versus positive findings ( 59.4 years ) ( P=0.031 ) . The overall survival at 48 months was 100 % for iPET-CT-negative GC-DLBCL patients and 61.2 % for iPET-CT-positive GC-DLBCL patients ( P=0.002 ) . Progression-free survival at 30 months was 100 % for iPET-CT-negative GC-DLBCL patients and 60.3 % for iPET-CT-positive GC-DLBCL patients ( P=0.001 ) . Conclusion We conclude that iPET-CT associated with cell origin identified a very good prognostic group in DLBCL patients treated with R-CHOP . Video Abstract : BACKGROUND Cyclophosphamide , doxorubicin , vincristine , and prednisolone ( CHOP ) is used to treat patients with non-Hodgkin lymphoma . Interval decrease from 3 weeks of treatment ( CHOP-21 ) to 2 weeks ( CHOP-14 ) , and addition of rituximab to CHOP-21 ( R-CHOP-21 ) has been shown to improve outcome in elderly patients with diffuse large B-cell lymphoma ( DLBCL ) . This r and omised trial assessed whether six or eight cycles of R-CHOP-14 can improve outcome of these patients compared with six or eight cycles of CHOP-14 . METHODS 1222 elderly patients ( aged 61 - 80 years ) were r and omly assigned to six or eight cycles of CHOP-14 with or without rituximab . Radiotherapy was planned to sites of initial bulky disease with or without extranodal involvement . The primary endpoint was event-free survival ; secondary endpoints were response , progression during treatment , progression-free survival , overall survival , and frequency of toxic effects . Analyses were done by intention to treat . The trial is registered on National Cancer Institute website , number NCT00052936 and as EU-20243 . FINDINGS 3-year event-free survival was 47.2 % after six cycles of CHOP-14 ( 95 % CI 41.2 - 53.3 ) , 53.0 % ( 47.0 - 59.1 ) after eight cycles of CHOP-14 , 66.5 % ( 60.9 - 72.0 ) after six cycles of R-CHOP-14 , and 63.1 % ( 57.4 - 68.8 ) after eight cycles of R-CHOP-14 . Compared with six cycles of CHOP-14 , the improvement in 3-year event-free survival was 5.8 % ( -2.8 - 14.4 ) for eight cycles of CHOP-14 , 19.3 % ( 11.1 - 27.5 ) for six cycles of R-CHOP-14 , and 15.9 % ( 7.6 - 24.2 ) for eight cycles of R-CHOP-14 . 3-year overall survival was 67.7 % ( 62.0 - 73.5 ) for six cycles of CHOP-14 , 66.0 % ( 60.1 - 71.9 ) for eight cycles of CHOP-14 , 78.1 % ( 73.2 - 83.0 ) for six cycles of R-CHOP-14 , and 72.5 % ( 67.1 - 77.9 ) for eight cycles of R-CHOP-14 . Compared with treatment with six cycles of CHOP-14 , overall survival improved by -1.7 % ( -10.0 - 6.6 ) after eight cycles of CHOP-14 , 10.4 % ( 2.8 - 18.0 ) after six cycles of R-CHOP-14 , and 4.8 % ( -3.1 - 12.7 ) after eight cycles of R-CHOP-14 . In a multivariate analysis that used six cycles of CHOP-14 without rituximab as the reference , and adjusting for known prognostic factors , all three intensified regimens improved 3-year event-free survival ( eight cycles of CHOP-14 : RR [ relative risk ] 0.76 [ 0.60 - 0.95 ] , p=0.0172 ; six cycles of R-CHOP-14 : RR 0.51 [ 0.40 - 0.65 ] , p<0.0001 ; eight cycles of R-CHOP-14 : RR 0.54 [ 0.43 - 0.69 ] , p<0.0001 ) . Progression-free survival improved after six cycles of R-CHOP-14 ( RR 0.50 [ 0.38 - 0.67 ] , p<0.0001 ) , and eight cycles of R-CHOP-14 ( RR 0.59 [ 0.45 - 0.77 ] , p=0.0001 ) . Overall survival improved only after six cycles of R-CHOP-14 ( RR 0.63 [ 0.46 - 0.85 ] , p=0.0031 ) . In patients with a partial response after four cycles of chemotherapy , eight cycles were not better than six cycles . INTERPRETATION Six cycles of R-CHOP-14 significantly improved event-free , progression-free , and overall survival over six cycles of CHOP-14 treatment . Response-adapted addition of chemotherapy beyond six cycles , though widely practice d , is not justified . Of the four regimens assessed in this study , six cycles of R-CHOP-14 is the preferred treatment for elderly patients , with which other approaches should be compared BACKGROUND The role of rituximab in combination with different CHOP ( cyclophosphamide , doxorubicin , v 
    Output:
    
Conclusions These findings showed that interim 18F-FDG PET has predictive value in DLBCL patients .