***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 The role and dose of anticoagulants in thromboprophylaxis for patients with cancer receiving chemotherapy through central venous catheters ( CVCs ) is controversial . We therefore assessed whether warfarin reduces catheter-related thrombosis compared with no warfarin and whether the dose of warfarin determines the thromboprophylactic effect . METHODS In 68 clinical centres in the UK , we r and omly assigned 1590 patients aged at least 16 years with cancer who were receiving chemotherapy through CVCs to no warfarin , fixed-dose warfarin 1 mg per day , or dose-adjusted warfarin per day to maintain an international normalised ratio between 1.5 and 2.0 . Clinicians who were certain of the benefit of warfarin r and omly assigned patients to fixed-dose or dose-adjusted warfarin groups . The primary outcome was the rate of radiologically proven , symptomatic catheter-related thrombosis . Analysis was by intention to treat . This trial is registered as an International St and ard R and omised Controlled Trial , number IS RCT N 50312145 . FINDINGS Compared with no warfarin ( n=404 ) , warfarin ( n=408 ; 324 [ 79 % ] on fixed-dose and 84 [ 21 % ] on dose-adjusted ) did not reduce the rate of catheter-related thromboses ( 24 [ 6 % ] vs 24 [ 6 % ] ; relative risk 0.99 , 95 % CI 0.57 - 1.72 , p=0.98 ) . However , compared with fixed-dose warfarin ( n=471 ) , dose-adjusted warfarin ( n=473 ) was superior in the prevention of catheter-related thromboses ( 13 [ 3 % ] vs 34 [ 7 % ] ; 0.38 , 0.20 - 0.71 , p=0.002 ) . Major bleeding events were rare ; an excess was noted with warfarin compared with no warfarin ( 7 vs 1 , p=0.07 ) and with dose-adjusted warfarin compared with fixed-dose warfarin ( 16 vs 7 , p=0.09 ) . A combined endpoint of thromboses and major bleeding showed no difference between comparisons . We did not note a survival benefit in either comparison . INTERPRETATION The findings show that prophylactic warfarin compared with no warfarin is not associated with a reduction in symptomatic catheter-related or other thromboses in patients with cancer and therefore we should consider newer treatments . FUNDING Medical Research Council and Cancer Research UK BACKGROUND Ambulatory cancer patients at high-risk for venous thromboembolism ( VTE ) can be identified using a vali date d risk score ( Khorana score ) . We evaluated the benefit of outpatient thromboprophylaxis with dalteparin in high-risk patients in a multicenter r and omized study . METHODS Cancer patients with Khorana score≥3 starting a new systemic regimen were screened for VTE and if negative r and omized to dalteparin 5000units daily or observation for 12weeks . Subjects were screened with lower extremity ultrasounds every 4weeks on study and with chest CT at 12weeks . The primary efficacy endpoint was all VTE over 12weeks and primary safety endpoint was clinical ly relevant bleeding events over 13weeks . The study was terminated early due to low accrual . RESULTS Of 117 enrolled patients , 10 ( 8.5 % ) had VTE on baseline screening and were not r and omized . Of 98 r and omized patients  , VTE occurred in 12 % ( N=6/50 ) of patients on dalteparin and 21 % ( N=10/48 ) on observation ( hazard ratio , HR 0.69 , 95 % CI 0.23 - 1.89 ) . Major bleeding was similar ( N=1 ) in each arm but clinical ly relevant bleeding was higher in dalteparin arm ( N=7 versus 1 on observation ) ( HR=7.0 , 95 % CI 1.2 - 131.6 ) . There was no difference in overall survival . CONCLUSIONS Thromboprophylaxis is associated with a non-significantly reduced risk of VTE and significantly increased risk of clinical ly relevant bleeding in this underpowered study . The Khorana score successfully identifies patients with high incidence of VTE both at baseline and during treatment . Future studies should continue to focus on risk-adapted approaches to reduce the burden of VTE in cancer . TRIAL REGISTRATION clinical trials.gov identifier : NCT00876915 Abstract Background Coagulation activation and venous thromboembolism ( VTE ) are hallmarks of malignant disease and represent a major cause of morbidity and mortality in cancer . Coagulation inhibition with low-molecular-weight heparin ( LMWH ) may improve survival specifically in small-cell lung cancer ( SCLC ) patients by preventing VTE and tumor progression ; however , r and omized trials with well-defined patient population s are needed to obtain conclusive data . The aim of RASTEN was to investigate the survival effect of LMWH enoxaparin in a homogenous population of SCLC patients . Patients and methods We carried out a r and omized , multicenter , open-label trial to investigate the addition of enoxaparin at a supraprophylactic dose ( 1 mg/kg ) to st and ard treatment in patients with newly diagnosed SCLC . The primary outcome was overall survival ( OS ) , and secondary outcomes were progression-free survival ( PFS ) , incidence of VTE and hemorrhagic events . Results In RASTEN , 390 patients were r and omized over an 8-year period ( 2008–2016 ) , of whom 186 and 191 were included in the final analysis in the LMWH and control arm , respectively . We found no evidence of a difference in OS or PFS by the addition of enoxaparin [ hazard ratio ( HR ) , 1.11 ; 95 % confidence interval ( CI ) 0.89–1.38 ; P = 0.36 and HR , 1.18 ; 95 % CI 0.95–1.46 ; P = 0.14 , respectively ] . Subgroup analysis of patients with limited and extensive disease did not show reduced mortality by enoxaparin . The incidence of VTE was significantly reduced in the LMWH arm ( HR , 0.31 ; 95 % CI 0.11–0.84 ; P = 0.02 ) . Hemorrhagic events were more frequent in the LMWH-treated group but fatal bleedings occurred in both arms . Conclusion LMWH enoxaparin in addition to st and ard therapy did not improve OS in SCLC patients despite being administered at a supraprophylactic dose and despite result ing in a significant reduction in VTE incidence . Addition of LMWH can not be generally recommended in the management of SCLC patients , and predictive biomarkers of VTE and LMWH-associated bleeding in cancer patients are warranted BACKGROUND Hemato-oncology patients treated with intensive chemotherapy usually require the placement of a central venous catheter ( CVC ) . CVCs are frequently complicated by catheter-related central venous thrombosis ( CVT ) , which has been associated with an increased risk of pulmonary embolism and catheter-related infection . OBJECTIVES To determine the efficacy and safety of thromboprophylaxis with s.c . low-molecular-weight heparin ( nadroparin ) administered once daily in a r and omized placebo-controlled , double-blind trial in patients with hematologic malignancies . PATIENTS AND METHODS Consecutive patients with hematologic malignancies requiring intensive chemotherapy including autologous stem cell transplantation were eligible . The patients were r and omized to receive nadroparin 2850 antifactor Xa units once daily or placebo s.c . for 3 weeks . Venography was performed on day 21 after CVC insertion . Secondary outcomes were bleeding and catheter-related infection . RESULTS In total , 113 patients were r and omized to nadroparin or placebo , and 87 patients ( 77 % ) underwent venography . In total , 11 venographically proven catheter-related CVTs were diagnosed . The frequency of catheter-related CVT was not significantly different between study groups , namely four catheter-related CVTs in the placebo group [ 9 % ; 95 % CI : 0.002 - 0.16 ] vs. seven catheter-related CVTs in the nadroparin group ( 17 % ; 95 % CI : 0.06 - 0.28 ) . In addition , no difference in the incidence of catheter-related infection or bleeding was observed between the groups . CONCLUSION This study showed that the actual risk for catheter-related CVT in patients with hematologic malignancies is lower than suggested in earlier studies in cancer patients . Although prophylactic administration of nadroparin appeared to be safe in this group of patients with a high risk of bleeding , it can not be recommended for the prevention of catheter-related CVT or catheter-related infection in patients with hematologic malignancies Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more By the use of 125I-labeled fibrinogen test , the incidence of postoperative deep vein thrombosis ( DVT ) and the effectiveness of prophylactic low-dose heparin treatment were investigated in 110 patients who underwent elective neurosurgical procedures . Fifty patients were appointed r and omly to a  control group and 50 to a heparin group ( 10 patients were excluded since they had DVT before surgery ) . The incidence of DVT was reduced from 34 % in the control group to 6 % in the heparin group ( p less than 0.005 ) . No statistically significant differences were observed in transfusion requirements , postoperative hemoglobin concentration , and the occurrence of postoperative hematomas between the two groups . Positive correlation was observed between DVT and motor deficit ( p less than 0.05 ) . Preoperative assessment of patients ' sensitivity to the st and ard 5000-unit dose of heparin was performed in all treated patients and is thought an important factor in improving the safety of heparin prophylaxis PURPOSE To provide current recommendations about the prophylaxis and treatment of venous thromboembolism ( VTE ) in patients with cancer . METHODS PubMed and the Cochrane Library were search ed for r and omized controlled trials , systematic review s , meta-analyses , and clinical practice guidelines from November 2012 through July 2014 . An up date committee review ed the identified abstract s. RESULTS Of the 53 publications identified and review ed , none prompted a change in the 2013 recommendations . RECOMMENDATIONS Most hospitalized patients with active cancer require thromboprophylaxis throughout hospitalization . Routine thromboprophylaxis is not recommended for patients with cancer in the outpatient setting . It may be considered for selected high-risk patients . Patients with multiple myeloma receiving antiangiogenesis agents with chemotherapy and /or dexamethasone should receive prophylaxis with either low-molecular weight heparin ( LMWH ) or low-dose aspirin .  Patients undergoing major surgery should receive prophylaxis starting before surgery and continuing for at least 7 to 10 days . Extending prophylaxis up to 4 weeks should be considered in those undergoing major abdominal or pelvic surgery with high-risk features . LMWH is recommended for the initial 5 to 10 days of treatment for deep vein thrombosis and pulmonary embolism as well as for long-term secondary prophylaxis ( at least 6 months ) . Use of novel oral anticoagulants is not currently recommended for patients with malignancy and VTE because of limited data in patients with cancer . Anticoagulation should not be used to extend survival of patients with cancer in the absence of other indications . Patients with cancer should be periodically assessed for VTE risk . Oncology professionals should educate patients about the signs and symptoms of VTE BACKGROUND Cancer patients receiving chemotherapy experience thromboembolic complications associated with the use of long-term indwelling central venous catheters ( CVCs ) . This prospect i ve , double-blind , placebo-controlled , multicenter study evaluated whether prophylactic treatment with a low molecular weight heparin could prevent clinical ly relevant catheter-related thrombosis . PATIENTS AND METHODS Patients with cancer undergoing chemotherapy for at least 12 weeks ( n=439 ) were r and omly assigned , in a 2:1 ratio , to receive either dalteparin ( 5000 IU ) or placebo , by subcutaneous injection , once daily for 16 weeks . Patients underwent upper extremity evaluation with either venography or ultrasound  at the time of a suspected  catheter-related complication ( CRC ) or upon completion of study medication . The primary end point , as determined by a blinded adjudication committee , was the occurrence of a CRC , defined as the first occurrence of any one of the following : clinical ly relevant catheter-related thrombosis that was symptomatic or that required anticoagulant or fibrinolytic  therapy ; catheter-related clinical ly 
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Conclusion Thromboprophylaxis did not increase major bleeding events or the incidence of thrombocytopenia .
All-cause mortality was not significantly different between those who received thromboprophylaxis and those who did not .
This meta- analysis provides evidence that thromboprophylaxis can reduce the number of VTE and DVT events , with no apparent increase in the incidence of major bleeding in patients with cancer