***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: UNLABELLED The aim of this study was to compare the value of review ing combined 18F-FDG PET/CT images with that of review ing side-by-side PET and CT images in the diagnosis of locoregional lymph node metastases in patients with esophageal squamous cell cancer . METHODS From November 2003 to December 2005 , 45 patients with thoracic esophageal squamous cell cancer underwent 18F-FDG PET/CT before surgery .  The results of review ing combined PET/CT images and side-by-side PET and CT images for the diagnosis of locoregional lymph node metastases were compared prospect ively in relation to pathologic findings . RESULTS All patients underwent successful surgery , and pathologic examination confirmed nodes positive for metastasis in 32 patients and 82 of 397 excised nodal groups . The sensitivity , specificity , accuracy , positive predictive value , and negative predictive value of PET/CT were 93.90 % ( 77/82 nodal groups ) , 92.06 % ( 290/315 ) , 92.44 % ( 367/397 ) , 75.49 % ( 77/102 ) , and 98.31 % ( 290/295 ) , respectively , whereas those of PET were 81.71 % ( 67/82 ) , 87.30 % ( 275/315 ) , 86.15 % ( 342/397 ) , 62.62 % ( 67/107 ) , and 94.83 % ( 275/290 ) , respectively . P values were 0.032 , 0.067 , 0.006 , 0.063 , and 0.037 , respectively . The differences in sensitivity , accuracy , and negative predictive value between PET and PET/CT were statistically significant . CONCLUSION PET/CT improves the sensitivity , accuracy , and negative predictive value of 18F-FDG imaging in the assessment of locoregional lymph nodes in thoracic esophageal squamous cell cancer and provides data of diagnostic significance OBJECTIVE Patients with advanced esophageal squamous cell carcinoma receive neoadjuvant chemotherapy or chemoradiotherapy to improve survival , but benefits are observed only in those with histologic response . Positron emission tomography with fludeoxyglucose F 18 ( INN fludeoxyglucose [ (18)F ] ) detects accumulation of glucose analog in viable cancer cells . This study investigated the usefulness of positron emission tomography with fludeoxyglucose F 18 in assessment of response of advanced esophageal squamous cell carcinoma to neoadjuvant treatment to establish new criteria to predict postoperative long-term survival . METHODS Fifty patients with locally advanced esophageal squamous cell carcinoma who received neoadjuvant therapy ( chemotherapy 35 , chemoradiotherapy 15 ) underwent positron emission tomography with fludeoxyglucose F 18 before surgical resection in evaluation of posttreatment maximum st and ardized uptake value , residual tumor size ( maximum square area of longitudinal axis ) , histologic response , and postoperative survival . RESULTS After treatment , uptake was not noted in 21 patients ( posttreatment maximum st and ardized uptake value < 2.5 , negative ) but was detected in 29 ( > or = 2.5 , positive ) . Residual tumor size ranged from 0 to 54.0 mm(2 ) for negative results and 55.0 to 676.0 mm(2 ) for positive , clearly distinguishing histologic major response from nonresponse . The negative group demonstrated significantly higher 5-year cause-specific survival ( 67.7 % ) and lower hematogenous recurrence ( 4.8 % ) than the 36.5 % and 37.0 % values in the positive group , ( P < .0042 and P = .0083 , respectively ) . Univariate Cox regression analyses identified posttreatment maximum st and ardized uptake value ( cutoff 2.5 ) as the only preoperative prognostic factor ( P = .0071 ) . CONCLUSION Posttreatment positron emission tomography with fludeoxyglucose F 18 reliably predicted histologic response and postoperative survival in advanced esophageal squamous cell carcinoma . This tool could potentially be used to tailor optimal treatment according to individual responses Background : Only responding patients benefit from preoperative therapy for locally advanced esophageal carcinoma . Early detection of non-responders may avoid futile treatment and delayed surgery . Patients and Methods : In a multi-center phase ll trial , patients with resectable , locally advanced esophageal carcinoma were treated with 2 cycles of induction chemotherapy followed by chemoradiotherapy ( CRT ) and surgery . Positron emission tomography with 2[fluorine-18]fluoro-2-deoxy-d-glucose ( FDG-PET ) was performed at baseline and after induction chemotherapy . The metabolic response was correlated with tumor regression grade ( TRG ) . A decrease in FDG tumor uptake of less than 40 % was prospect ively hypothesized as a predictor for histopathological non-response ( TRG > 2 ) after CRT . Results : 45 patients were included . The median decrease in FDG tumor uptake after chemotherapy correlated well with TRG after completion of CRT ( p = 0.021 ) . For an individual patient , less than 40 % decrease in FDG tumor uptake after induction chemotherapy predicted histopathological non-response after completion of CRT , with a sensitivity of 68 % and a specificity of 52 % ( positive predictive value 58 % , negative predictive value 63 % ) . Conclusions : Metabolic response correlated with histopathology after preoperative therapy . However , FDG-PET did not predict non-response after induction chemotherapy with sufficient clinical accuracy to justify withdrawal of subsequent CRT and selection of patients to proceed directly to surgery Purpose The purpose of this study was to evaluate the impact of FDG-PET following chemoradiotherapy ( CRT ) on treatment planning and survival in patients with oesophageal cancer ( OC ) . Methods Fifty-three consecutive OC patients had a post-treatment PET scan to evaluate tumour response to CRT prior to possible surgery . Baseline pre-CRT PET was performed in 33 patients . Prospect ively recorded post-CRT management plans were compared with post-PET treatment . High impact was defined as a change in treatment intent or modality . Survival was analysed using the Kaplan-Meier product limit method and Cox proportional hazards regression model . Results After completion of CRT , 23/53 patients ( 43 % ) achieved complete metabolic response ( CMR ) , as compared with only four ( 8 % ) with complete response on computed tomography .  High PET impact was observed in 19 patients ( 36 % ) . CMR was strongly predictive of survival ( p<0.008 ) on multivariate analysis . CMR patients in whom resection was not performed had comparable survival to those ( CMR and non-CMR ) who underwent resection . Conclusion The use of post-treatment FDG-PET for assessment of tumour response after CRT changed the clinical management of more than one-third of OC patients .  CMR status as assessed by PET powerfully stratified prognosis . Even in the absence of a baseline study , normalisation of uptake at all sites of known tumoral involvement carries a good medium-term prognosis Preoperative staging for esophageal adenocarcinoma is suboptimal for predicting outcomes when compared with pathological data . The aim of this study was to assess if the quantitative values obtained by preoperative 18F-fluorodeoxyglucose positron emission tomography ( FDG-PET ) are independent prognostic indicators for survival in patients with resectable adenocarcinoma of the esophagus undergoing surgical treatment without neoadjuvant therapy . Patients were identified from a prospect i ve data base , survival analyses were undertaken using log rank and Cox method . The median follow-up was 44 months ( range 18 - 61 months ) . Between November 2002 and November 2005 , 45 consecutive patients underwent FDG-PET followed by surgery . The median age was 72 years ( range 38 - 82 years ) . On univariate analysis of overall survival and disease-free survival , preoperative FDG-PET maximum st and ardized uptake value ( SUV(max ) ; P= 0.008 and P= 0.015 , respectively ) and postoperative pathological stage ( P= 0.001 and P= 0.001 , respectively ) as well as postoperative histological grade ( P= 0.001 and P= 0.001 , respectively ) were significantly associated with outcome . Multivariate analysis demonstrated that only the postoperative pathological variables were independent predictors of outcome ( Wald 11.81 , P= 0.001 ) . Preoperative  FDG-PET SUV(max ) is associated with outcome after esophageal adenocarcinoma resection but remains less accurate than postoperative variables . A high  FDG-PET SUV(max ) could be used to identify a high-risk population who would benefit most from neoadjuvant therapies AIM To document the impact of integrated positron-emission tomography and computed tomography ( PET/CT ) on the management of a cohort of UK patients undergoing PET/CT as part of their staging investigations for potentially curable oesophageal cancer . MATERIAL S AND METHODS A multicentre , prospect i ve study of newly diagnosed patients with oesophageal cancer undergoing PET/CT was set up across five cancer networks covering a total population of 6.6 million . Data were prospect ively collected for cases diagnosed between 1 November 2006 and 31 October 2007 . RESULTS One hundred and ninety-one patients underwent PET/CT  , with 31 ( 16 % ) positive for possible metastatic disease . Amongst the 31 positive examinations , 18 ( 9.4 % ) were confirmed to have metastatic disease , and 13 ( 6.5 % ) patients had no subsequent evidence of metastatic disease , although in three ( 1.6 % ) of these a second previously unsuspected pathology was diagnosed . Two patients had false-negative PET/CT and were found to have metastatic disease . The results of the PET/CT examination down-staged 10 ( 5 % ) patients thought to have coeliac/M1a node involvement on CT . Fifteen of 110 ( 13 % ) patients with stage 3 or 4 disease at CT and endoscopic ultrasound ( EUS ) had confirmed metastatic disease at PET/CT , compared with none of 18 with stage 2b , three of 52 ( 6 % ) with stage 2a , and none of 10 with stage 1 disease . CONCLUSION This study confirms the role of PET/CT in a multicentre UK setting in the management of patients with potentially curable carcinoma of the oesophagus , improving the accuracy of pre-treatment staging compared with CT and EUS alone . Early tumours infrequently show evidence of metastasis on PET/CT , although further data are required to confidently determine the stage of tumours where PET/CT has no additional value Objectives The objectives of this study were to reveal the utility of 18F-fluorodeoxyglucose positron emission tomography ( FDG-PET ) within 7 days after chemoradiotherapy to predict prognosis in patients with postoperative recurrent esophageal cancer . Material s and methods Patients scheduled to undergo concurrent chemoradiotherapy for postoperative locoregional recurrence of esophageal cancer were recruited . Selection criteria were : ( 1 ) locoregional recurrence , ( 2 ) no previous radiation therapy , ( 3 ) planning treatment with concurrent chemoradiotherapy , ( 4 ) FDG-PET performed < 2 weeks before chemoradiotherapy , and ( 5 ) no serious diabetes .  FDG-PET was performed < 7 days after chemoradiotherapy . No more treatment after chemoradiotherapy was given until disease progression was diagnosed according to the Response Evaluation Criteria in Solid Tumors ( RECIST ) . Correlations of FDG-PET findings with cause-specific survival and local control rates were investigated prospect ively . Results Twenty patients were enrolled . Median observation period of patients who survived was 45.0 months . Median maximum st and ardized uptake value ( SUVmax ) after chemoradiotherapy was 2.4 , and median SUVmax before chemoradiotherapy was 8.4 . Cause-specific survival and local control rates were significantly better for patients with SUVmax ≤ 2.4 after chemoradiotherapy ( log-rank test , P = 0.033 and 0.010 , respectively ) . SUVmax before chemoradiotherapy tended to be correlated only with cause-specific survival rate ( log-rank test , P = 0.076 ) . Change in metabolic activity of FDG was significantly correlated with local control rate ( log-rank test , P = 0.042 ) . Conclusions FDG-PET performed even < 7 days after chemoradiotherapy predicts prognosis in patients with postoperative recurrent esophageal cancer Purpose To evaluate the clinical impact of FDG-PET in staging oesophageal cancer and whether this information improves prognostic stratification . Methods Impact was based on comparison of a prospect ively recorded pre-PET plan with post 
    Output:
    
PET is recommended to improve the accuracy of M staging for the staging work-up of patients with oesophageal cancer who are potential c and i date s for curative therapy .
Due to insufficient evidence , no recommendation was made for or against the use of PET for the assessment of treatment response and the evaluation of suspected recurrence