***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 
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    Input: PURPOSE Experimental studies and indirect clinical evidence suggest that low molecular weight heparins may have antineoplastic effects . We investigated the influence of a low molecular weight heparin dalteparin on the survival of patients with active cancer and acute venous thromboembolism . PATIENTS AND METHODS Survival data were examined in a posthoc analysis in patients with solid tumors and venous thromboembolism who were r and omly assigned to dalteparin or a coumarin derivative for 6 months in a multicenter , open-label , r and omized , controlled trial . All-cause mortality at 12 months was compared between treatment groups in patients with and without metastatic malignancy . The effect of dalteparin on survival was compared between the two patient subgroups . RESULTS During the 12-month follow-up period , 356 of 602 patients with solid tumors and acute venous thromboembolism  died . Among patients without metastatic disease , the probability of death at 12 months was 20 % in the dalteparin group , as compared with 36 % in the oral anticoagulant group ( hazard ratio , 0.50 ; 95 % CI , 0.27 to 0.95 ; P = .03 ) . In patients with metastatic cancer , no difference in mortality between the treatment groups was observed ( 72 % and 69 % , respectively ; hazard ratio , 1.1 ; 95 % CI , 0.87 to 1.4 ; P = .46 ) . The observed effects of dalteparin on survival were statistically significantly different between patients with and without metastatic disease ( P = .02 ) . CONCLUSION The use of dalteparin relative to coumarin derivatives was associated with improved survival in patients with solid tumors who did not have metastatic disease at the time of an acute venous thromboembolic event . Additional studies are warranted to investigate these findings BACKGROUND Several studies have reported that patients who present with idiopathic deep vein thrombosis ( DVT ) have an increased risk of subsequently developing cancer . A clinical trial had previously been conducted examining the optimal duration of oral anticoagulant therapy following initial heparin treatment in patients with proximal DVT . METHODS A historical cohort study was performed on patients enrolled in the duration of anticoagulant trial . Patients known to have cancer at the time of entry into the trial were excluded . The qualifying DVTs were classified as idiopathic ( no known associated risk factors ) or secondary without knowledge of subsequent recurrent venous thrombosis or cancer . The patients were then followed for the development of cancer . RESULTS Thirteen ( 8.6 % ) of the 152 patients in the idiopathic cohort subsequently developed cancer compared to eight ( 7.1 % ) of 112 patients in the secondary cohort , P = 0.86 . Two ( 5.4 % ) of 37 patients with recurrent venous thromboembolism and 19 ( 8.4 % ) of 227 patients without recurrent thromboembolism developed cancer , P = 0.7 . CONCLUSION Our study did not detect an increased risk of subsequent cancer in patients presenting with idiopathic DVT compared to secondary DVT ; nor did we detect an increased incidence of cancer in patients with recurrent venous thromboembolism . Further studies are required prior to pursuing a policy of aggressive screening for cancer in patients with idiopathic venous thromboembolism OBJECTIVE This study was undertaken to assess a potential relationship between idiopathic deep venous thrombosis ( DVT ) and occult cancer . DESIGN Prospect i ve study with a 2-year follow-up . SETTING The Angiology Unit of the First Department of Surgery , University of Athens , Greece , a tertiary referral centre . SUBJECTS Two hundred and ninety-three patients with a first episode of venographically or Doppler-proved DVT were included in the study , of whom 264 were followed up for 2 years . INTERVENTIONS After an initial extensive diagnostic workup , including routine blood counts and chemistries , erythrocyte sedimentation rate , CEA levels , chest X-ray and abdominopelvic CT scan , all patients were closely followed up and periodically examined . MAIN OUTCOME MEASURES The incidence of cancer amongst patients with idiopathic and secondary DVT , and the validity of our screening programme . RESULTS Cancer was diagnosed in 21 out of 84 patients with idiopathic DVT ( 25 % ) as compared with eight out of 202 patients with secondary DVT ( 4 % ) . In 22 out of the 29 cases , cancer was detected during the initial admission , and the remaining seven cases were detected during follow-up . Cancer was diagnosed in 15 asymptomatic , healthy individuals , but only in seven of them was the diagnosis made by CT scan . CONCLUSION Occult cancer is fairly common in patients with idiopathic DVT , but the routine use of extensive diagnostic studies for its detection remains to be vali date d by further prospect i ve studies BACKGROUND A strong association between bilateral deep vein thrombosis ( DVT ) and cancer had been found in one retrospective study . To confirm this finding , consecutive patients with an objective diagnosis of bilateral DVT were followed over 12 months . PATIENTS AND METHODS One-hundred and three patients , hospitalized for bilateral DVT , were included in the study . Twenty-six patients ( 25.2 % ) were already known to have a cancer , 26 ( 25.2 % ) had a previous history of venous thromboembolic disease , 44 ( 42.7 % ) had a symptomatic pulmonary embolism . The patients were scheduled to be prospect ively followed up at 3 , 6 and 12 months as out patients . Information on recurrence , evidence of a new overt cancer and the cause of death were recorded for all patients . RESULTS A new cancer was diagnosed in 20 ( 26 % ) of the 77 patients without known cancer at admission . The risk of cancer was significantly more important in idiopathic thrombosis than in patients with secondary thrombosis ( 40.5 % vs. 12.5 % ; odds ratio 4.8 , 95 % confidence interval 1.4 , 18.8 ) . Seventy percent of the cancers discovered had already spread . Age , gender , presence of pulmonary embolism , recurrence and location of the thrombosis were not statistically associated with the risk of cancer . The 1-year survival rates of patients with a previously known cancer and patients with a newly discovered cancer were , respectively , 26 % and 35 % ( P = 0.33 ) . CONCLUSIONS Bilateral DVT is a significant risk indicator of malignancy . Cancer is present in 45 % of patients with bilateral DVT and is associated with a poor prognosis A small proportion of patients with deep vein thrombosis develop recurrent venous thromboembolic complications or bleeding during anticoagulant treatment . These complications may occur more frequently if these patients have concomitant cancer . This prospect i ve follow-up study sought to determine whether in thrombosis patients those with cancer have a higher risk for recurrent venous thromboembolism or bleeding during anticoagulant treatment than those without cancer . Of the 842 included patients , 181 had known cancer at entry . The 12-month cumulative incidence of recurrent thromboembolism in cancer patients was 20.7 % ( 95 % CI , 15.6%-25.8 % ) versus 6.8 % ( 95 % CI , 3.9%- 9.7 % ) in patients without cancer , for a hazard ratio of 3.2 ( 95 % CI , 1.9 - 5.4 ) The 12-month cumulative incidence of major bleeding was 12.4 % ( 95 % CI , 6.5%-18.2 % ) in patients with cancer and 4.9 % ( 95 % CI , 2.5%-7.4 % ) in patients without cancer , for a hazard ratio of 2.2 ( 95 % CI , 1.2 - 4.1 ) . Recurrence and bleeding were both related to cancer severity and occurred predominantly during the first month of anticoagulant therapy but could not be explained by sub- or overanticoagulation . Cancer patients with venous thrombosis are more likely to develop recurrent thromboembolic complications and major bleeding during anticoagulant treatment than those without malignancy . These risks correlate with the extent of cancer . Possibilities for improvement using the current paradigms of anticoagulation seem limited and new treatment strategies should be developed We prospect ively studied 78 consecutive patients with acute pulmonary embolism ( PE ) to determine the most appropriate workup study for search ing for hidden cancer . After a careful physical examination , the following tests were performed :  erythrocyte sedimentation rate ( ESR ) , complete blood cell counts , biochemistry , carcinoembryonic antigen levels , chest radiograph , upper gastrointestinal endoscopy , and abdominal ultrasound .  If a malignant lesion was suspected , further appropriate tests were performed . After hospital discharge , periodic follow-up was performed on all patients in our outpatient clinic . A malignant lesion was detected in 9 of 78 patients : in 7 of them , cancer was diagnosed during the hospital admission because of acute PE . All but one of these 7 patients were asymptomatic , except for PE symptoms . In three of them some abnormalities on physical examination led to the diagnosis of cancer ; in the remaining three patients the diagnosis was suspected from abnormal results of blood tests . Cancer was detected several months after hospital discharge in two additional patients : an esophageal cancer was diagnosed 5 months later in one of the 23 patients who refused endoscopy ; and a colonic carcinoma was detected 21 months after hospital discharge in a patient in whom colonoscopy was not performed at the time of hospital admission . When considered overall , cancer was more commonly found in patients with " idiopathic " PE as compared with patients with known risk factors for PE development ( 6 of 21 patients vs 3 of 51 patients ; p < 0.05 ) . On the other h and , one patient died because of massive recurrent PE after a biopsy sample was obtained because of a prostatic node . Gross hematuria had developed shortly after biopsy , and any attempt to increase heparin doses was followed by recurrent hematuria . According to our experience , any decision about procedures that potentially involve bleeding should be carefully individualized in patients with acute PE 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 Recruitment to r and omized controlled trials can be difficult for all parties involved . An alternative to the st and ard process has been suggested for trials in which the control group receives st and ard treatment or nontreatment . In this approach ( the Zelen design ) , r and omization precedes consent , which is only sought from those allocated to the experimental arm of a trial . The control group is thus unaware that r and omization has taken place . As a controversial method , this approach has been often suggested but rarely used . Here we describe how 44 parents recruited to a difficult neonatal trial that used conventional r and omization  reacted to the idea of Zelen r and omization . The arguments they gave for and against the method pertain to four areas : the giving or withholding of information , the effect on decision making , the use of data without parental knowledge , and the long-term impact for parents . The parents were evenly divided in accepting or rejecting the method . Further analysis showed that those rejecting Zelen r and omization were more likely to be parents of infants allocated to the control group . This suggests that those from whom consent would not be sought , the group that this approach is primarily meant to protect , are most likely to find it unacceptable Thromboembolic ( TE ) events preceding cancer have been observed . Some studies failed to find this correlation . We retrospectively examined the  cancer incidence following thromboembolic events in patients at our medical center . Medical records of 183 patients 
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A thrombosis developed overnight , which does n't leave me any doubt of the nature of my disease ( 5 ) .