***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: BACKGROUND Radiofrequency ablation ( RFA ) is safe and effective for eradicating Barrett 's esophagus ( BE ) and BE-associated early neoplasia . Most RFA studies have limited the baseline length of BE ( < 10 cm ) , and therefore little is known about RFA for longer BE . OBJECTIVE To assess the safety and efficacy of RFA with or without prior endoscopic resection ( ER ) for BE ≥ 10 cm containing neoplasia . DESIGN Prospect i ve trial . SETTING Two tertiary-care centers . PATIENTS This study involved consecutive patients with BE ≥ 10 cm with early neoplasia . INTERVENTION Focal ER for visible abnormalities , followed by a maximum of 2 circumferential and 3 focal RFA procedures every 2 to 3 months until complete remission . MAIN OUTCOME MEASUREMENTS Complete remission , defined as endoscopic resolution of BE and no intestinal metaplasia ( CR-IM ) or neoplasia ( CR-neoplasia ) in biopsy specimens . RESULTS Of the 26 patients included , 18 underwent ER for visible abnormalities before RFA . The ER specimens showed early cancer in 11 , high- grade intraepithelial neoplasia ( HGIN ) in 6 , and low- grade intraepithelial neoplasia ( LGIN ) in 1 . The worst residual histology , before RFA and after any ER , was HGIN in 16 patients and LGIN in 10 patients . CR-neoplasia and CR-IM were achieved in 83 % ( 95 % confidence interval [ CI ] , 63%-95 % ) and 79 % ( 95 % CI , 58%-93 % ) , respectively . None of the patients had fatal or severe complications and 15 % ( 95 % CI , 4%-35 % ) had moderate complications . During a mean ( ± st and ard deviation ) follow-up of 29 ( ± 9.1 ) months , no neoplasia recurred . LIMITATIONS Tertiary-care center , short follow-up . CONCLUSION ER for visible abnormalities , followed by RFA of residual BE is a safe and effective treatment for BE ≥ 10 cm containing neoplasia , with a low chance of recurrence of neoplasia or BE during follow-up OBJECTIVES : Patients with Barrett 's esophagus ( BE ) have an increased risk of developing esophageal adenocarcinoma ( EAC ) . As the absolute risk remains low , there is a need for predictors of neoplastic progression to tailor more individualized surveillance programs . The aim of this study was to identify such predictors of progression to high- grade dysplasia ( HGD ) and EAC in patients with BE after 4 years of surveillance  and to develop a prediction model based on these factors . METHODS : We included 713 patients with BE ( ≥2 cm ) with no dysplasia ( ND ) or low- grade dysplasia ( LGD ) in a multicenter , prospect i ve cohort study . Data on age , gender , body mass index ( BMI ) , reflux symptoms , tobacco and alcohol use , medication use , upper gastrointestinal ( GI ) endoscopy findings , and histology were prospect ively collected . As part of this study , patients with ND underwent surveillance every 2 years , whereas those with LGD were followed on a yearly basis . Log linear regression analysis was performed to identify risk factors associated with the development of HGD or EAC during surveillance . RESULTS : After 4 years of follow-up , 26/713 ( 3.4 % ) patients developed HGD or EAC , with the remaining 687 patients remaining stable with ND or LGD . Multivariable analysis showed that a known duration of BE of ≥10 years ( risk ratio ( RR ) 3.2 ; 95 % confidence interval ( CI ) 1.3–7.8 ) , length of BE ( RR 1.11 per cm increase in length ; 95 % CI 1.01–1.2 ) , esophagitis ( RR 3.5 ; 95 % CI 1.3–9.5 ) , and LGD ( RR 9.7 ; 95 % CI 4.4–21.5 ) were significant predictors of progression to HGD or EAC . In a prediction model , we found that the annual risk of developing HGD or EAC in BE varied between 0.3 % and up to 40 % . Patients with ND and no other risk factors had the lowest risk of developing HGD or EAC ( < 1 % ) , whereas those with LGD and at least one other risk factor had the highest risk of neoplastic progression ( 18–40 % ) . CONCLUSIONS : In patients with BE , the risk of developing HGD or EAC is predominantly determined by the presence of LGD , a known duration of BE of ≥10 years , longer length of BE , and presence of esophagitis . One or combinations of these risk factors are able to identify patients with a low or high risk of neoplastic progression and could therefore be used to individualize surveillance intervals in BE BACKGROUND Barrett 's esophagus ( BE ) may lead to high- grade dysplasia ( HGD ) and adenocarcinoma . The objective was to examine the impact of treating patients with BE and with HGD by using porfimer sodium ( POR ) and photodynamic therapy ( PDT ) for ablating HGD and reducing the incidence of esophageal adenocarcinoma . METHODS The design was a multicenter , partially blinded ( pathology ) , r and omized clinical trial conducted in patients with BE who have HGD . There were 30 contributing centers . A total of 485 patients were screened , with 208 in the intent-to-treat population and 202 in the safety population . Patients were r and omized on a 2:1 basis to compare PDT with POR plus omeprazole ( PORPDT ) with omeprazole only ( OM ) . The main outcome measurement was complete HGD ablation occurring at any time during the study period . RESULTS There was a significant difference ( p < 0.0001 ) in favor of PORPDT ( 106/138 [ 77 % ] ) compared with OM ( 27/70 [ 39 % ] ) in complete ablation of HGD at any time during the study period . The occurrence of adenocarcinoma in the PORPDT group ( 13 % ) ( n=18 ) was significantly lower ( p < 0.006 ) compared with the OM group ( 28 % ) [ corrected ] ( n=20 ) . The safety profile showed 94 % of patients in the PORPDT group and 13 % of patients in the OM group had treatment-related adverse effects . The limitations of the study were that PDT therapy may have had to be applied more than once and that patients spent more time in treatment . The patients and the physicians were not blinded to the treatment . CONCLUSIONS PORPDT in conjunction with omeprazole is an effective therapy for ablating HGD in patients with BE and in reducing the incidence of esophageal adenocarcinoma BACKGROUND The aim of this study was to evaluate the endoscopic and the histologic effects of a balloon-based bipolar radiofrequency electrode for ablation of porcine and human esophageal epithelium . METHODS All procedures were performed with a balloon-based , bipolar radiofrequency system that creates a circumferential , thin-layer epithelial ablation zone within the esophagus . In Phase I , multiple ablations  were created in 10 farm swine , followed by acute euthanasia and histologic assessment for completeness of epithelial removal and ablation depth . In Phase II , multiple ablations were created in 19 farm swine , with varying power and energy density , followed by endoscopy at 2 and 4 weeks to assess stricture formation . In Phase III , 3 ablations were created in 12 farm swine , with varying energy density ( 5 , 8 , 10 , 12 , 15 , or 20 J/cm 2 ) at 350 W. Animals were euthanized at 48 hours . Histologic examination determined the percentage of epithelium removed and the ablation depth . In Phase IV , 3 patients underwent esophageal epithelial ablation before esophagectomy , creating separate lesions proximal to the tumor . Completeness of epithelial ablation and ablation depth was quantified histologically . RESULTS In Phase I , complete removal of esophageal epithelium was achieved at energy density setting s of 9.7 to 29.5 J/cm 2 . In Phase II , 9.7 and 10.6 J/cm 2 produced no stricture , whereas more than 20 J/cm 2 produced a stricture in every case . In Phase III , 8 - 20 J/cm 2 result ed in 100 % epithelial ablation . Five and 8 J/cm 2 spared the muscularis mucosae , whereas 10 J/cm 2 caused injury to the muscularis mucosae but preserved the submucosa . In Phase IV , histologic examination demonstrated full-thickness epithelial removal in areas of electrode contact . Ablation extended only to the muscularis mucosae , without injury to submucosa . CONCLUSIONS In the porcine and the human esophagus , circumferential , full-thickness ablation of epithelium without direct injury to the submucosa is possible and was well tolerated . In all cases , depth of ablation was linearly related to energy density of treatment OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity OBJECTIVE To assess the dose-response , safety , and efficacy of circumferential endoscopic ablation of Barrett 's esophagus ( BE ) by using an endoscopic balloon-based ablation device ( HALO360 System ) . DESIGN This study was conducted in 2 serial phases ( dosimetry phase and effectiveness phase ) to evaluate a balloon-based ablation device that delivers a pre-set amount of energy density ( J/cm2 ) to BE tissue . The dosimetry phase evaluated the dose-response and the safety of delivering 6 to 12 J/cm2 . The effectiveness phase used 10 J/cm2 ( delivered twice [ x2 ] ) for all patients , followed by EGD with biopsies at 1 , 3 , 6 , and 12 months . A second ablation procedure was performed if BE was present at 1 or 3 months . Patients received esomeprazole 40 mg twice a day for 1 month after ablation , and 40 mg every day thereafter . Postablation symptoms were quantified by using a 14-day symptom diary ( scale , 0 - 100 ) . A complete response ( CR ) was defined as all biopsy specimens negative for BE at 12 months . SETTING Eight U.S. centers , between September 2003 and September 2005 . PATIENTS Patients were 18 to 75 years of age , with a diagnosis of BE ( without dysplasia ) , with histopathology reconfirmation of the diagnosis within 6 months of enrollment . RESULTS In the dosimetry phase , 32 patients ( 29 men ; mean age , 56.8 years ) were enrolled . Median symptom scores returned to a score of 0 of 100 by day 3 . There were no dose-related serious adverse events , and the outcomes at 1 and 3 months permitted the selection of 10 J/cm2 ( x2 ) for the subsequent effectiveness phase of the study . In the effectiveness phase , 70 patients ( 52 men , 18 women ; 
    Output:
    
Treatment of BE with RFA results in CE-D and CE-IM in a high proportion of patients , with few recurrences of IM after treatment and a low rate of adverse events .