***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: All 68,308 inhabitants of Göteborg born between 1918 and 1931 were r and omly divided into a test and a control group . The subjects in the test group were invited to perform Hemoccult II fecal occult blood testing  on 3 days and to repeat the test after 16 to 24 months . In the prevalence screening 21,347 ( 63 % ) performed the test , and in the rescreening 19,991 ( 60 % ) . Investigation of the 942 ( 4.4 % ) with positive tests in the prevalence screening showed 47 cancers and 129 subjects with adenomas > or = 1.0 cm . In the rescreening 5.1 % had a positive test , and 34 cancers and 122 subjects with adenomas ( > or = 1.0 cm ) were found among those . Cancer had also been diagnosed in 19 subjects in the interval between the two screening occasions and in 15 subjects among the non-responders . Forty-four cancers had been diagnosed in the control group during the same period . Cancers detected by screening were at a less advanced stage than in the control group . It is too early to show any effect of  screening  on mortality from colorectal cancer 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 . ) IMPORTANCE Although some countries have implemented widespread colonoscopy screening , most European countries have not introduced it because of uncertainty regarding participation rates , procedure-related pain and discomfort , endoscopist performance , and effectiveness . To our knowledge , no r and omized trials on colonoscopy screening currently exist . OBJECTIVE To investigate participation rate , adenoma yield , performance , and adverse events of population -based colonoscopy screening  in several European countries . DESIGN , SETTING , AND POPULATION A population -based r and omized clinical trial was conducted among 94 959 men and women aged 55 to 64 years of average risk for colon cancer in Pol and , Norway , the Netherl and s , and Sweden from June 8 , 2009 , to June 23 , 2014 . INTERVENTIONS Colonoscopy screening or no screening . MAIN OUTCOMES AND MEASURES Participation in colonoscopy screening , cancer and adenoma yield , and participant experience . Study outcomes were compared by country and endoscopist . RESULTS Of 31 420 eligible participants r and omized to the colonoscopy group , 12 574 ( 40.0 % ) underwent screening .  Participation rates were 60.7 % in Norway ( 5354 of 8816 ) , 39.8 % in Sweden ( 486 of 1222 ) , 33.0 % in Pol and ( 6004 of 18 188 ) , and 22.9 % in the Netherl and s ( 730 of 3194 ) ( P < .001 ) . The cecum intubation rate was 97.2 % ( 12 217 of 12 574 ) , with 9726 participants ( 77.4 % ) not receiving sedation . Of the 12 574 participants undergoing colonoscopy screening , we observed 1 perforation ( 0.01 % ) , 2 postpolypectomy serosal burns ( 0.02 % ) , and 18 cases of bleeding owing to polypectomy ( 0.14 % ) . Sixty-two individuals ( 0.5 % ) were diagnosed with colorectal cancer and 3861 ( 30.7 % ) had adenomas , of which 1304 ( 10.4 % ) were high-risk adenomas . Detection rates were similar in the proximal and distal colon . Performance differed significantly between endoscopists ; recommended benchmarks for cecal intubation ( 95 % ) and adenoma detection ( 25 % ) were not met by 6 ( 17.1 % ) and 10 of 35 endoscopists ( 28.6 % ) , respectively . Moderate or severe abdominal pain after colonoscopy was reported by 601 of 3611 participants ( 16.7 % ) examined with st and ard air insufflation vs 214 of 5144 participants ( 4.2 % ) examined with carbon dioxide ( CO2 ) insufflation ( P < .001 ) . CONCLUSIONS AND RELEVANCE Colonoscopy screening entails high detection rates in the proximal and distal colon . Participation rates and endoscopist performance vary significantly . Postprocedure abdominal pain is common with st and ard air insufflation and can be significantly reduced by using CO2 . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00883792 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 To test the reliability and validity of specific instructions to classify blinding , when unclearly reported in r and omized trials , as " probably done " or " probably not done . " STUDY DESIGN AND SETTING We assessed blinding of patients , health care providers , data collectors , outcome adjudicators , and data analysts in 233 r and omized trials in duplicate and independently using detailed instructions . The response options were " definitely yes , " " probably yes , " " probably no , " and " definitely no. " We contacted authors for data verification ( 46 % response ) . For each of the five questions , we assessed reliability by calculating the agreement between the two review ers and validity by calculating the agreement between review ers ' consensus and verified data . RESULTS The percentage with unclear blinding status varied between 48.5 % ( patients ) and 84.1 % ( data analysts ) . Reliability was moderate for blinding of outcome adjudicators ( κ=0.52 ) and data analysts ( κ=0.42 ) and substantial for blinding of patients ( κ=0.71 ) , providers ( κ=0.68 ) , and data collectors ( κ=0.65 ) . The raw agreement between the consensus record and the author-verified record varied from 84.1 % ( blinding of data analysts ) to 100 % ( blinding of health care providers ) . CONCLUSION With the possible exception of blinding of data analysts , use of " probably yes " and " probably no " instead of " unclear " may enhance the assessment of blinding in trials Background : Participation in cancer screening programmes might cause worries in the population outweighting the benefits of reduced mortality . The present study aim ed to investigate possible psychological harm of participation in a  colorectal cancer ( CRC ) screening pilot in Norway . Methods : In a prospect i ve , r and omised trial participants ( aged 50–74 years ) were invited to either  flexible sigmoidoscopy ( FS ) screening , faecal immunochemical test ( FIT ) , or no screening ( the control group ; 1 : 1 : 1 ) . Three thous and two hundred and thirteen screening participants ( 42 % of screened individuals ) completed the Hospital Anxiety and Depression Scale question naire as well as the SF-12—a health-related quality of life ( HRQOL ) question naire when invited to screening and when receiving the screening result . A control group was invited to complete the question naires only . Two thous and six hundred and eighteen control participants ( 35 % of invited individuals ) completed the question naire . Results : A positive screening result did not increase participants ’ level of anxiety or depression , or decrease participants ’ level of HRQOL . Participants who received a negative result reported decreased anxiety and improvement on some HRQOL dimensions . However , no change was considered to be of clinical relevance . Conclusion : The current study showed no clinical ly relevant psychological harm of receiving a positive CRC screening result or of participating in FS or FIT screening , in a Norwegian population BACKGROUND A single flexible sigmoidoscopy at around the age of 60 years has been proposed as an effective strategy for colorectal cancer ( CRC ) screening . METHODS We conducted a r and omized controlled trial to evaluate the effect of flexible sigmoidoscopy screening on CRC incidence and mortality . A question naire to assess the eligibility and interest in screening was mailed to 236,568 men and women , aged 55 - 64 years , who were r and omly selected from six trial centers in Italy . Of the 56,532 respondents , interested and eligible subjects were r and omly assigned to the intervention group ( invitation for flexible sigmoidoscopy ; n = 17,148 ) or the control group ( no further contact ; n = 17,144 ) , between June 14 , 1995 , and May 10 , 1999 .  Flexible sigmoidoscopy was performed on 9911 subjects . Intention-to-treat and per- protocol analyses were performed to compare the CRC incidence and mortality rates in the intervention and control groups . Per- protocol analysis was adjusted for noncompliance . RESULTS A total of 34,272 subjects ( 17,136 in each group ) were included in the follow-up analysis . The median follow-up period was 10.5 years for incidence and 11.4 years for mortality ; 251 subjects were diagnosed with CRC in the intervention group and 306 in the control group . Overall incidence rates in the intervention and control groups were 144.11 and 176.43 , respectively , per 100,000 person-years 
    Output:
    
No screening test reduced mortality nor incidence by more than six per 1000 screened over 15 years .
Conclusions In a 15-year perspective , sigmoidoscopy reduces colorectal cancer incidence , while sigmoidoscopy , annual and biennial gFOBT all reduce colorectal cancer mortality .
Sigmoidoscopy may reduce colorectal cancer incidence and mortality more in men than in women .