***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 In r and omized trials , fecal occult-blood testing reduces mortality from colorectal cancer . However , the duration of the benefit is unknown , as are the effects specific to age and sex . METHODS In the Minnesota Colon Cancer Control Study , 46,551 participants , 50 to 80 years of age , were r and omly assigned to usual care ( control ) or to annual or biennial screening with fecal occult-blood testing . Screening was performed from 1976 through 1982 and from 1986 through 1992 . We used the National Death Index to obtain up date d information on the vital status of participants and to determine causes of death through 2008 . RESULTS Through 30 years of follow-up , 33,020 participants ( 70.9 % ) died . A total of 732 deaths were attributed to colorectal cancer : 200 of the 11,072 deaths ( 1.8 % ) in the annual-screening group , 237 of the 11,004 deaths ( 2.2 % ) in the biennial-screening group , and 295 of the 10,944 deaths ( 2.7 % ) in the control group . Screening reduced colorectal-cancer mortality ( relative risk with annual screening , 0.68 ; 95 % confidence interval [ CI ] , 0.56 to 0.82 ; relative risk with biennial screening , 0.78 ; 95 % CI , 0.65 to 0.93 ) through 30 years of follow-up . No reduction was observed in all-cause mortality ( relative risk with annual screening , 1.00 ; 95 % CI , 0.99 to 1.01 ; relative risk with biennial screening , 0.99 ; 95 % CI , 0.98 to 1.01 ) . The reduction in colorectal-cancer mortality was larger for men than for women in the biennial-screening group ( P=0.04 for interaction ) . CONCLUSIONS The effect of screening with fecal occult-blood testing on colorectal-cancer mortality persists after 30 years but does not influence all-cause mortality . The sustained reduction in colorectal-cancer mortality supports the effect of polypectomy . ( Funded by the Veterans Affairs Merit Review Award Program and others . ) BACKGROUND Although tests for occult blood in the feces are widely used to screen for colorectal cancers , there is no conclusive evidence that they reduce mortality from this cause . We evaluated a fecal occult-blood test  in a r and omized trial and documented its effectiveness . METHODS We r and omly assigned 46,551 participants 50 to 80 years of age to screening for colorectal cancer once a year , to  screening every two years , or to a control group .  Participants who were screened su bmi tted six guaiac-impregnated paper slides with two smears from each of three consecutive stools . About 83 percent of the slides were rehydrated . Participants who tested positive underwent a diagnostic evaluation that included colonoscopy .  Vital status was ascertained for all study participants during 13 years of follow-up . A committee determined causes of death . A single pathologist determined the stage of each tissue specimen . Differences in mortality from colorectal cancer , the primary study end point , were monitored with the sequential log-rank statistic . RESULTS The 13-year cumulative mortality per 1000 from colorectal cancer was 5.88 in the annually screened group ( 95 percent confidence interval , 4.61 to 7.15 ) , 8.33 in the biennially screened group ( 95 percent confidence interval , 6.82 to 9.84 ) , and 8.83 in the control group ( 95 percent confidence interval , 7.26 to 10.40 ) . The rate in the annually screened group , but not in the biennially screened group , was significantly lower than that in the control group . Reduced mortality in the annually screened group was accompanied by improved survival in those with colorectal cancer and a shift to detection at an earlier stage of cancer . CONCLUSIONS Annual fecal occult-blood testing with rehydration of the sample s decreased the 13-year cumulative mortality from colorectal cancer by 33 percent Objective Faecal immunochemical testing ( FIT ) is increasingly used in colorectal cancer ( CRC ) screening but has a less than perfect sensitivity . Combining risk stratification , based on established risk factors for advanced neoplasia , with the FIT result for allocating screenees to colonoscopy could increase the sensitivity and diagnostic yield of FIT-based screening . We explored the use of a risk prediction model in CRC screening . Design We collected data in the colonoscopy arm of the Colonoscopy or Colonography for Screening study , a multicentre screening trial . For this study 6600 r and omly selected , asymptomatic men and women between 50 years and 75 years of age were invited to undergo colonoscopy .  Screening participants were asked for one sample FIT ( OC-sensor ) and to complete a risk question naire prior to colonoscopy . Based on the question naire data and the FIT results , we developed a multivariable risk model with the following factors : total calcium intake , family history , age and FIT result . We evaluated goodness-of-fit , calibration and discrimination , and compared it with a model based on primary screening with FIT only . Results Of the 1426 screening participants , 1112 ( 78 % ) completed the question naire and FIT . Of these , 101 ( 9.1 % ) had advanced neoplasia . The risk based model significantly increased the goodness-of-fit compared with a model based on FIT only ( p<0.001 ) . Discrimination improved significantly with the risk-based model ( area under the receiver operating characteristic ( ROC ) curve : from 0.69 to 0.76 , ( p=0.02 ) ) . Calibration was good ( Hosmer-Lemeshow test ; p=0.94 ) . By offering colonoscopy to the 102 patients at highest risk , rather than to the 102 cases with a FIT result > 50 ng/mL , 5 more cases of advanced neoplasia would be detected ( net reclassification improvement 0.054 , p=0.073 ) . Conclusions Adding risk based stratification increases the accuracy FIT-based CRC screening and could be used in pre selection for colonoscopy in CRC screening programmes BACKGROUND There is growing evidence that faecal-occult-blood ( FOB ) screening may reduce colorectal cancer ( CRC ) mortality , but this reduction in CRC mortality has not been shown in an unselected population -based r and omised controlled trial . The aim of this study was to assess the effect of FOB screening on CRC mortality in such a setting . METHODS Between February , 1981 , and January , 1991 , 152,850 people aged 45 - 74 years who lived in the Nottingham area of the UK were recruited to our study . Participants were r and omly allocated FOB screening ( 76,466 ) or no screening ( controls ; 76,384 ) . Controls were not told about the study and received no intervention . Screening-group participants were sent a Haemoccult FOB test kit with instructions from their family doctor . FOB tests were not rehydrated and dietary restrictions were imposed only for retesting borderline results . Individuals with negative FOB tests at the first screening , together with those who tested positive but in whom no neoplasia was found on colonoscopy , were invited to take part in further screening every 2 years . Screening was stopped in February , 1995 , by which time screening-group participants had been offered FOB tests between three and six times . Screening-group participants who had a positive test were offered full colonoscopy . All participants were followed up until June , 1995 . The primary outcome measure was CRC mortality . FINDINGS Of the 152,850 individuals recruited to the study , 2599 could not be traced or had emigrated and were excluded from the analysis . Thus , there were 75,253 participants in the screening group and 74,998 controls . 44,838 ( 59.6 % ) screening-group participants completed at least one screening . 28,720 ( 38.2 % ) of these individuals completed all the FOB tests they were offered and 16,118 ( 21.4 % ) completed at least one screening but not all the tests they were offered . 30,415 ( 40.4 % ) did not complete any test . Of 893 cancers ( 20 % stage A ) diagnosed in  screening-group participants ( CRC incidence of 1.49 per 1000 person-years ) , 236 ( 26.4 % ) were detected by FOB screening , 249 ( 27.9 % ) presented after a negative FOB test or investigation , and 400 ( 44.8 % ) presented in non-responders . The incidence of cancer in the control group ( 856 cases , 11 % stage A ) was 1.44 per 1000 person-years . Median follow-up was 7.8 years ( range 4.5 - 14.5 ) . 360 people died from CRC in the screening group compared with 420 in the control group-a 15 % reduction in cumulative CRC mortality in the screening group ( odds ratio=0.85 [ 95 % ; CI 0.74 - 0.98 ] , p = 0.026 ) . INTERPRETATION Our findings together with evidence from other trials suggest that consideration should be given to a national programme of FOB screening to reduce CRC mortality in the general population Background : Previous studies have suggested that the immunochemical fecal occult blood test has superior specificity for detecting bleeding in the lower gastrointestinal tract even if bleeding occurs in the upper tract . We conducted a large population -based study involving asymptomatic adults in Taiwan , a population with prevalent upper gastrointestinal lesions , to confirm this cl aim . Methods : We conducted a prospect i ve cohort study involving asymptomatic people aged 18 years or more in Taiwan recruited to undergo an immunochemical fecal occult blood test , colonoscopy and esophagogastroduodenoscopy between August 2007 and July 2009 . We compared the prevalence of lesions in the lower and upper gastrointestinal tracts between patients with positive and negative fecal test results . We also identified risk factors associated with a false-positive fecal test result . Results : Of the 2796 participants , 397 ( 14.2 % ) had a positive fecal test result . The sensitivity of the test for predicting lesions in the lower gastrointestinal tract was 24.3 % , the specificity 89.0 % , the positive predictive value 41.3 % , the negative predictive value 78.7 % , the positive likelihood ratio 2.22 , the negative likelihood ratio 0.85 and the accuracy 73.4 % . The prevalence of lesions in the lower gastrointestinal tract was higher among those with a positive fecal test result than among those with a negative result ( 41.3 % v. 21.3 % , p < 0.001 ) . The prevalence of lesions in the upper gastrointestinal tract did not differ significantly between the two groups ( 20.7 % v. 17.5 % , p = 0.12 ) . Almost all of the participants found to have colon cancer ( 27/28 , 96.4 % ) had a positive fecal test result ; in contrast , none of the three found to have esophageal or gastric cancer had a positive fecal test result ( p < 0.001 ) . Among those with a negative finding on colonoscopy , the risk factors associated with a false-positive fecal test result were use of antiplatelet drugs ( adjusted odds ratio [ OR ] 2.46 , 95 % confidence interval [ CI ] 1.21–4.98 ) and a low hemoglobin concentration ( adjusted OR 2.65 , 95 % CI 1.62–4.33 ) . Interpretation : The immunochemical fecal occult blood test was specific for predicting lesions in the lower gastrointestinal tract . However , the test did not adequately predict lesions in the upper gastrointestinal tract Background : Faecal occult blood tests ( FOBTs ) are used for colorectal cancer ( CRC ) screening . We aim ed to assess the sensitivity of an immunochemical FOBT for detecting advanced colorectal neoplasia in the left vs the right colon and to explore reasons for potential differences in site-specific test performance . Methods : We prospect ively measured faecal occult blood levels by a quantitative immunochemical FOBT ( RIDASCREEN ) in 2310 average-risk subjects undergoing screening colonoscopy .  We compared diagnostic performance for subjects with left- vs right-sided advanced neoplasia , as well as patient characteristics and adenoma characteristics that have been suggested to impact faecal haemoglobin levels . Results : Sensitivities for subjects with left- vs right-sided advanced neoplasia were 33 % ( 95 % confidence interval ( CI ) , 26–41 % ) and 20 % ( CI , 11–31 % ) ( P=0.04 ) at a specificity of 95 % ( overall sensitivity : 29 % ) and the areas under the receiver-operating characteristics curve were 0.71 ( CI 
    Output:
    
Use of the fecal immunochemical test ( FIT ) for human globulin is more sensitive and specific than guaiac-based fecal occult blood testing for CRC and advanced adenomas and has higher rates of participation and acceptance ( 1416 ) .