***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: 18F-Fluorodesoxyglucose Positron-Emission-Tomography combined with Computed-Tomography ( FDG PET/CT ) might be an attractive tool for cancer screening in patients with venous thromboembolism ( VTE ) , allowing non-invasive whole-body imaging . One of the frequent criticisms to the use of FDG PET/CT for screening is the potential for false positive results leading to unnecessary/invasive investigations . Our aim was to compare the frequency and invasiveness of additional testing following extensive and limited screening strategies for occult malignancy in patients with unprovoked VTE . We analysed patients included in the MVTEP study , a r and omized trial that compared a screening strategy based on FDG-PET/CT with a limited screening strategy for occult malignancy diagnosis in patients with unprovoked VTE . All additional diagnostic procedures following screening were recorded and classified as invasive or non-invasive . A total of 394 patients were analysed . Additional diagnostic procedures realized in patients of each group consisted of 59 tests in patients of the FDG PET/CT group versus 53 tests among the patients from the limited screening group ( p=0.65 ) . Overall , 45 ( 22.8 % ) patients in the FDG PET/CT group underwent additional diagnostic tests , versus 32 ( 16.2 % ) in the limited screening group ( absolute risk difference+6.6 % , 95 % CI -1.3 to + 14.4 % , p=0.13 ) . Sixteen ( 8.1 % ) patients in the FDG PET/CT group underwent invasive procedures , versus 6 ( 3 % ) in the limited screening group ( absolute risk difference+5.1 % , 95 % CI + 0.5 to + 10.0 % , p=0.03 ) . We found no statistical difference in the number of additional procedures following each screening strategy . However , a higher number of invasive tests were performed in the FDG PET/CT group BACKGROUND Patients with a first episode of idiopathic venous thromboembolism ( IVTE ) have an estimated 10 % incidence of cancer within 12 months after diagnosis . However , the utility of screening for cancer in this population is controversial . METHODS In this prospect i ve concurrently controlled cohort study , limited and extensive cancer screening strategies were compared . All 630 patients underwent baseline screening consisting of history , physical examination , basic laboratory tests and chest X-ray . In the extensive screening group abdominal and chest CT scan and mammography were added . Outcomes were incidence and curability of cancer , and cancer-related and overall mortality . RESULTS In 12 of the 342 ( 3.5 % ) patients in the extensive screening group malignancy was diagnosed at baseline compared with 2.4 % ( seven of 288 patients ) in the limited screening group . Extensive screening detected six additional cancers ( 2.0 % ; 95 % CI , 0.74 - 4.3 ) , of which three were potentially curable . During a median 2.5 years of follow-up , cancer was diagnosed in 3.7 % and 5.0 % in the extensive and limited screening groups , respectively . In the extensive screening group 26 patients ( 7.6 % ) died compared with 24 ( 8.3 % ) in the limited screening group ; adjusted hazard ratio 1.22 ( 95 % CI , 0.69 - 2.22 ) . Of these deaths 17 ( 5.0 % ) in the extensive screening group and 8 ( 2.8 % ) in the limited screening group were cancer related ; adjusted hazard ratio 1.79 ( 95 % CI , 0.74 - 4.35 ) . CONCLUSIONS The low yield of extensive screening and lack of survival benefit do not support routine screening for cancer with abdominal and chest CT scan and mammography in patients with a first episode of IVTE Patients with unprovoked venous thromboembolism ( VTE ) may harbor occult cancer . Whether an extensive diagnostic work-up for cancer has additional value over a more limited screening for detection of underlying malignancy in these patients is controversial . We performed a r and omized multicenter trial to assess if in patients with unprovoked VTE , a computed tomography (CT)-based diagnostic strategy including thoracic , abdominal , and pelvic CT in combination with fecal occult blood test yields a higher cancer detection rate than a nonst and ardized testing approach based on physicians ' clinical judgment and patients ' preferences . Cancer-free patients were followed up for up to 24 months . Of the 195 consecutive patients with unprovoked VTE who were eligible for this investigation , an occult cancer was identified in 10 of the 98 patients ( 10.2 % ) r and omized to the CT-based strategy , and in 8 of the 97 ( 8.2 % ) allocated to the personalized strategy ( absolute difference , 2.0 % ; 95 % confidence interval , -7.2 - 11.1 ; p = 0.81 ) . During follow-up , cancer was identified in an additional 2 patients in each group . Overall , 7 ( 7.1 % ) patients of the CT-based strategy died , as compared with 11 ( 11.3 % ) of the personalized strategy , with 2 and 4 , respectively , due to cancer . In conclusion , a CT-based strategy in combination with fecal occult blood test does not provide a clinical ly significant benefit over more limited cancer screening for detecting occult cancer in patients with unprovoked VTE . ( Clinical Trials.gov number , NCT00361647 ) Abstract . The objective of this prospect i ve study was to evaluate the sensitivity , specificity , positive and negative predictive values , and interobserver agreement in the diagnosis of pulmonary embolism with helical CT , compared with pulmonary angiography , for both global results and for selective vascular territories . Helical CT and pulmonary angiography were performed on 66 consecutive patients with clinical suspicion of pulmonary embolism . The exams were blindly interpreted by a vascular radiologist and by two independent thoracic radiologists . Results were analyzed for the final diagnosis as well as separately for 20 different arterial territories in each patient . Pulmonary angiography revealed embolism in 25 patients ( 38 % ) ; 48 % were main , 28 % lobar , 16 % segmental , and 8 % subsegmental . The sensitivity , specificity , and positive and negative predictive values of helical CT for observer 1 were , respectively , 91 , 81.5 , 75 , and 94 % ; in 7.5 % of the patients the exam was considered indeterminate . For observer 2 the values were , respectively , 88 , 86 , 81.5 , and 91 % ; in 9 % of the patients the exam was considered indeterminate . Main arteries were considered as non-valuable in 0–0.8 % , the lobar in 1.5 % , the segmental in 7.5–8.5 % , and the subsegmental in 55–60 % . Interobserver agreement for the final diagnosis was 80 % ( kappa 0.65 ) . For each vascular territory , this was 98 % ( kappa 0.91 ) for main arteries , 92 % ( kappa 0.78 ) for lobar arteries , 79 % ( kappa 0.56 ) for segmental arteries , and 59 % ( kappa 0.21 ) for subsegmental arteries . Helical CT is a reliable method for pulmonary embolism diagnosis , with good interobserver agreement for main , lobar , and segmental territories . Worse results are found for subsegmental arteries , with high incidence of non-valuable branches and poor interobserver agreement BACKGROUND Patients with cancer have a substantial risk of recurrent thrombosis despite the use of oral anticoagulant therapy . We compared the efficacy of a low-molecular-weight heparin with that of an oral anticoagulant agent in preventing recurrent thrombosis in patients with cancer . METHODS Patients with cancer who had acute , symptomatic proximal deep-vein thrombosis , pulmonary embolism , or both were r and omly assigned to receive low-molecular-weight heparin ( dalteparin ) at a dose of 200 IU per kilogram of body weight subcutaneously once daily for five to seven days and a coumarin derivative for six months ( target international normalized ratio , 2.5 ) or dalteparin alone for six months ( 200 IU per kilogram once daily for one month , followed by a daily dose of approximately 150 IU per kilogram for five months ) . RESULTS During the six-month study period , 27 of 336 patients in the dalteparin group had recurrent venous thromboembolism , as compared with 53 of 336 patients in the oral-anticoagulant group ( hazard ratio , 0.48 ; P=0.002 ) . The probability of recurrent thromboembolism at six months was 17 percent in the oral-anticoagulant group and 9 percent in the dalteparin group . No significant difference between the dalteparin group and the oral-anticoagulant group was detected in the rate of major bleeding ( 6 percent and 4 percent , respectively ) or any bleeding ( 14 percent and 19 percent , respectively ) . The mortality rate at six months was 39 percent in the dalteparin group and 41 percent in the oral-anticoagulant group . CONCLUSIONS In patients with cancer and acute venous thromboembolism , dalteparin was more effective than an oral anticoagulant in reducing the risk of recurrent thromboembolism without increasing the risk of bleeding Thirty patients with deep vein thrombosis of the legs of less than four days ' duration were allocated at r and om to treatment with heparin , streptokinase , or Arvin under laboratory control . When the fate of the thrombi was assessed by objective techniques — phlebography and the 125I-labelled fibrinogen test — the incidence of complete thrombolysis was greatest in the streptokinase group . Complications arose during treatment in each group but were least with Arvin . The natural history of the disease favours clinical but not always anatomical recovery Patients with symptomatic idiopathic venous thromboembolism and apparently cancer-free have an approximate 10 % incidence of subsequent cancer . Apparently cancer-free patients with acute idiopathic venous thromboembolism were r and omized to either the strategy of extensive screening for occult cancer or to no further testing . Patients had a 2-year follow-up period . Of the 201 patients , 99 were allocated to the extensive screening group and 102 to the control group .  In 13 ( 13.1 % ) patients , the extensive screening identified occult cancer . In the extensive screening group , a single ( 1.0 % ) malignancy became apparent during follow-up , whereas in the control group a total of 10 ( 9.8 % ) malignancies became symptomatic [ relative risk , 9.7 ( 95 % CI , 1.3 - 36.8 ; P < 0.01 ] . Overall , malignancies identified in the extensive screening group were at an earlier stage and the mean delay to diagnosis was reduced from 11.6 to 1.0 months ( P < 0.001 ) . Cancer-related mortality during the 2 years follow-up period occurred in two ( 2.0 % ) of the 99 patients of the extensive screening group vs. four ( 3.9 % ) of the 102 control patients [ absolute difference , 1.9 % ( 95 % CI , -5.5 - 10.9 ) ] . Although early detection of occult cancers may be associated with improved treatment possibilities , it is uncertain whether this improves the prognosis BACKGROUND Clear guidelines for the investigation of occult malignancy after unprovoked venous thromboembolism are not yet available . (18)F-fluorodeoxyglucose ( (18)F-FDG ) PET/CT could serve as a comprehensive screening strategy for occult malignancy in this context . We aim ed to compare a screening strategy based on (18)F-FDG PET/CT with a limited screening strategy for detection of malignant disease in patients with unprovoked venous thromboembolism . METHODS In an open-label , multicentre , r and omised study we enrolled patients from four French university hospitals . Patients aged 18 years or older , diagnosed with unprovoked venous thromboembolism ( not provoked by a major inherited or acquired risk factor ) were invited to participate . Patients were r and omly assigned in a 1:1 ratio to a limited screening strategy ( physical examination , usual laboratory tests , and basic radiographs ) or a screening strategy consisting of the limited strategy plus an (18)F-FDG PET/CT scan . R and omisation was done with a dedicated central web-based r and omisation system , in block sizes of six , stratified by centre , and concealed from the investigators . Patients and investigators were not masked to study group assignment . Patients were followed up for 2 years . The primary outcome was the proportion of patients with a cancer diagnosis in each group after the initial screening assessment . Analyses were conducted in modified intention-to-test and per- protocol population s. This trial is completed and registered with Clinical Trials.gov , number NCT00964275 . FINDINGS Between March 3 , 2009 , and Aug 18 , 2012 , we enrolled and r and omly assigned 399 patients ; five withdrew consent , leaving 197 in each group for the modified intention-to-test analysis . After initial screening assessment , cancer was diagnosed in 11 ( 5·6 % ) patients in the (18)F-FDG 
    Output:
    
AUTHORS ' CONCLUSIONS Testing for cancer in people with unprovoked VTE may lead to earlier diagnosis of cancer at an earlier stage of the disease .
However , there is currently insufficient evidence to draw definitive conclusions concerning the effectiveness of testing for undiagnosed cancer in people with a first episode of unprovoked VTE ( DVT or PE ) in reducing cancer and VTE-related morbidity and mortality .
The results could be consistent with either benefit or no benefit .