***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 Screening for colorectal cancer is widely recommended , but the preferred strategy remains unidentified . We aim ed to compare participation and diagnostic yield between screening with colonoscopy and with non-cathartic CT colonography . METHODS Members of the general population , aged 50 - 75 years , and living in the regions of Amsterdam or Rotterdam , identified via the registries of the regional municipal administration , were r and omly allocated ( 2:1 ) to be invited for primary screening  for colorectal cancer by colonoscopy or by CT colonography . R and omisation was done per household with a minimisation algorithm based on age , sex , and socioeconomic status . Invitations were sent between June 8 , 2009 , and Aug 16 , 2010 . Participants assigned to CT colonography who were found to have one or more large lesions ( ≥10 mm ) were offered colonoscopy ; those with 6 - 9 mm lesions were offered surveillance CT colonography . The primary outcome was the participation rate , defined as number of invitees undergoing the examination relative to the total number of invitees . Diagnostic yield was calculated as number of participants with advanced neoplasia relative to the total number of invitees . Invitees and screening centre employees were not masked to allocation . This trial is registered in the Dutch trial register , number NTR1829 . FINDINGS 1276 ( 22 % ) of 5924 colonoscopy invitees participated , compared with 982 ( 34 % ) of 2920 CT colonography invitees ( relative risk [ RR ] 1·56 , 95 % CI 1·46 - 1·68 ; p<0·0001 ) . Of the participants in the colonoscopy group , 111 ( 9 % ) had advanced neoplasia of whom seven ( < 1 % ) had a carcinoma . Of CT colonography participants , 84 ( 9 % ) were offered colonoscopy , of whom 60 ( 6 % ) had advanced neoplasia of whom five ( < 1 % ) had a carcinoma ; 82 ( 8 % ) were offered surveillance . The diagnostic yield for all advanced neoplasia was 8·7 per 100 participants for colonoscopy versus 6·1 per 100 for CT colonography ( RR 1·46 , 95 % CI 1·06 - 2·03 ; p=0·02 ) and 1·9 per 100 invitees for colonoscopy and 2·1 per 100 invitees for CT colonography ( RR 0·91 , 0·66 - 2·03 ; p=0·56 ) . The diagnostic yield for advanced neoplasia of 10 mm or more was 1·5 per 100 invitees for colonoscopy and 2·0 per 100 invitees for CT colonography , respectively ( RR 0·74 , 95 % CI 0·53 - 1·03 ; p=0·07 ) . Serious adverse events related to the screening procedure were post-polypectomy bleedings : two in the colonoscopy group and three in the CT colonography group . INTERPRETATION Participation in colorectal cancer screening with CT colonography was significantly better than with colonoscopy , but colonoscopy identified significantly more advanced neoplasia per 100 participants than did CT colonography .  The diagnostic yield for advanced neoplasia per 100 invitees was similar for both strategies , indicating that both techniques can be used for population -based screening for colorectal cancer . Other factors such as cost-effectiveness and perceived burden should be taken into account when deciding which technique is preferable . FUNDING Netherl and s Organisation for Health Research and Development , Centre for Translational Molecular Medicine , and the Nuts Ohra Foundation BACKGROUND Adenoma detection rate ( ADR ) has become the most important quality indicator for colonoscopy . OBJECTIVE The aim of this study was to investigate which modifiable factors , directly related to the endoscopic procedure , influenced the ADR in screening colonoscopies . DESIGN Observational , nested study . SETTING Multicenter , r and omized , controlled trials . PATIENTS Asymptomatic people aged 50 to 69 years were eligible for a multicenter , r and omized , controlled trial design ed to compare colonoscopy and fecal immunochemical testing in colorectal cancer screening . A total of 4539 individuals undergoing a direct screening colonoscopy  were included in this study . INTERVENTION Colonoscopy . MAIN OUTCOME MEASUREMENTS Bowel cleansing , sedation , withdrawal time in normal colonoscopies , and cecal intubation were analyzed as possible predictors of adenoma detection by using logistic regression analysis , adjusted for age and sex . RESULTS In multivariate analysis , after adjustment for age and sex , factors independently related to the ADR were a mean withdrawal time longer than 8 minutes ( odds ratio [ OR ] 1.51 ; 95 % CI , 1.17 - 1.96 ) in normal colonoscopies and split preparation ( OR 1.26 ; 95 % CI , 1.01 - 1.57 ) . For advanced adenomas , only withdrawal time maintained statistical significance in the multivariate analysis . For proximal adenomas , withdrawal time and cecal intubation maintained independent statistical significance , whereas only withdrawal time longer than 8 minutes and a < 10-hour period between the end of preparation and colonoscopy showed independent associations for distal adenomas . LIMITATIONS Only endoscopic variables have been analyzed . CONCLUSION Withdrawal time was the only modifiable factor related to the ADR in colorectal cancer screening colonoscopies associated with an increased detection rate of overall , advanced , proximal , and distal adenomas BACKGROUND AND STUDY AIM Following acute diverticulitis , colonoscopy is advised to rule out malignancy . Commonly , the colonoscopy is postponed to avoid the potential risk of perforation . In a previous pilot , noncontrolled study , we showed that early colonoscopy is feasible in patients with acute diverticulitis . This r and omized controlled trial compared early and late colonoscopy in hospitalized patients with acute diverticulitis . PATIENTS AND METHODS 154 patients diagnosed with acute diverticulitis were hospitalized between January 2004 and June 2006 . Of these , 35 patients were excluded because of either free perforation or pericolic air on computed tomography ( CT ) , and another 18 because they had undergone colonoscopy in the previous year . The remaining 101 patients were offered the possibility of participating in the study , with r and om allocation to either early in-hospital colonoscopy or late colonoscopy , 6 weeks later . R and omization was refused by 15 patients , and 86 were included in the study . RESULTS 45 patients were r and omly allocated for early colonoscopy and 41 for late colonoscopy . Three and 10 did not present for the examination , in the early and late group respectively . The cecum could not be reached in eight and three patients from the early and late groups , respectively . The colonoscopy revealed polyps in five patients , two in the early group and three in the late group . No malignancy was detected . There were no complications in either group . CONCLUSIONS Early colonoscopy in acute diverticulitis is feasible and safe in the absence of pericolic air on CT , and has greater compliance . However , no added value is apparent compared with the CT scan currently used BACKGROUND Although the risk of bowel perforation is often cited as a major factor in the choice between colonoscopy and sigmoidoscopy for colorectal screening , good estimates of the absolute and relative risks of perforation are lacking . METHODS We used a large population -based cohort that consisted of a r and om sample of 5 % of Medicare beneficiaries living in regions of the United States covered by the Surveillance , Epidemiology , and End Results ( SEER ) Program registries to determine rates of perforation in people aged 65 years and older . We identified individuals who were cancer-free and had undergone colonoscopy or sigmoidoscopy between 1991 and 1998 , calculated both the incidence and risk of perforation within 7 days of the procedure , and explored the impact on incidence and risk of perforation of age , race/ethnicity , sex , comorbidities , and indication for the procedure . We also estimated the risk of death after perforation . Risks were calculated with odds ratios ( ORs ) and 95 % confidence intervals ( CIs ) . All statistical tests were two-sided . RESULTS There were 77 perforations after 39 286 colonoscopies ( incidence = 1.96/1000 procedures ) and 31 perforations after 35 298 sigmoidoscopies ( incidence = 0.88/1000 procedures ) . After adjustment , the OR for perforation from colonoscopy relative to perforation from sigmoidoscopy was 1.8 ( 95 % CI = 1.2 to 2.8 ) . Risk of perforation from either procedure increased in association with increasing age ( P(trend)<.001 for both procedures ) and the presence of two or more comorbidities ( P(trend)<.001 for colonoscopy and P(trend ) = .03 for sigmoidoscopy ) . Compared with those who were endoscopied and did not have a perforation , the risk of death was statistically significantly increased for those who had a perforation after either colonoscopy ( OR = 9.0 , 95 % CI = 3.0 to 27.3 ) or sigmoidoscopy ( OR = 8.8 , 95 % CI = 1.6 to 48.5 ) . The risk of perforation after colonoscopy , especially for screening procedures , declined during the 8-year study period . CONCLUSIONS The risk of perforation after colonoscopy is approximately double that after sigmoidoscopy , but this difference appears to be decreasing . These observations should be useful to clinicians making screening and diagnostic decisions for individual patients and to policy officials setting guidelines for colorectal cancer screening programs Several risk factors for colorectal cancer ( CRC ) have been identified . If individuals with risk factors are more likely to harbor cancer or it precursors screening programs should be targeted toward this population . We evaluated the predictive value of colorectal cancer risk factors for the detection of advanced colorectal adenoma in a population based  CRC colonoscopy screening program . Data were collected in a multicenter trial conducted in the Netherl and s , in which 6600 asymptomatic men and women between 50 and 75 years were r and omly selected from a population registry . They were invited to undergo a screening colonoscopy . Based on a review of the literature CRC risk factors were selected . Information on risk factors was obtained from screening attendees through a question naire . For each CRC risk factor , we estimated its odds ratio ( OR ) relative to the presence of advanced neoplasia as detected at colonoscopy . Of the 1426 screening participants who underwent a colonoscopy , 1236 ( 86 % ) completed the risk question naire . 110 participants ( 8.9 % ) had advanced neoplasia . The following risk factors were significantly associated with advanced neoplasia detected by colonoscopy : age ( OR : 1.06 per year ; 95 % CI : 1.03 - 1.10 ) , calcium intake ( OR : 0.99 per mg ; 95 % CI : 0.99 - 1.00 ) , positive CRC family history ( OR : 1.55 per first degree family member ; 95%CI : 1.11 - 2.16 ) and smoking ( OR : 1.75 ; 95%CI : 1.09 - 2.82 ) . Elderly screening participants , participants with lower calcium intake , a CRC family history , and smokers are at increased risk of harboring detectable advanced colorectal neoplasia at screening colonoscopy To define the syndrome of vasovagal reactions that occur during colonoscopy and to identify those risk factors associated with this development , we prospect ively evaluated patients undergoing colonoscopy with monitored sedation .  A total of 223 consecutive patients were evaluated during the 60-day study period . A vasovagal reaction was defined as the occurrence of one or more of the following : diaphoresis , sustained bradycardia of less than 60 beats/min or a decrease in heart rate of 10 % , or hypotension ( systolic blood pressure less than 90 mm Hg , diastolic blood pressure less than 60 mm Hg , or a reduction in blood pressure of more than 10 % below a baseline measurement before colonoscopy and after sedation ) . Thirty-seven ( 16.5 % ) of the 223 patients experienced a vasovagal reaction by our criteria . The remaining 186 patients did not ; 100 of these patients were r and omly selected by computer to form a control group . No statistically significant differences were observed between the vasovagal and control groups with regard to demographics , cardiopulmonary disease , cardiac medications , procedure success , the endoscopist , patient procedure tolerance , colon preparation , or procedure difficulty . A significant difference was seen in the mean dose of midazolam used in the vasovagal group as compared with that used in the control group ( 4.6 mg versus 3.9 mg , p < 0.04 ) , and moderate to severe diverticulosis was more commonly seen in the vasovagal group as compared with the control group ( 43 % versus 16 % , p < 0.02 ) . Thirteen ( 35 % ) of the 37 patients who had a vasovagal reaction required medical intervention ( 5.8 % of the 223 patients ) . ( ABSTRACT TRUNCATED AT 250 WORDS BACKGROUND Serrated cancers account for 10 % to  
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Because of high sensitivity of 94 % , a specificity of 99 % , and a low interobserver variability , this modality is currently preferred for the diagnosis of diverticulitis , although US also has a good sensitivity .
Apart from diagnosing CRC , the detection of AA is of great importance because it bears the potential to progress to carcinoma .
Colonoscopy is accompanied by such disadvantages as invasiveness and discomfort , potential adverse events such as perforation , and additional costs .