***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: The disease natural history of colorectal neoplasm regarding two opposing theories , adenoma – carcinoma sequence and de novo carcinoma theory , is controversial and rarely quantified . The aims of this study are therefore to estimate the dwelling times of adenoma – carcinoma sequence by adenoma size and histological type , taking de novo carcinoma into account . The efficacy of polypectomy  was therefore estimated making allowance for two pathways . A case – cohort design , underpinning a cohort with 13 908 subjects ( including 10 496 normal subjects , 2652 polyps , 760 colorectal cancers ) who underwent the first examination of colonoscopy between 1979 and 1998 , was devised to estimate parameters associated with two opposing theories by r and omly selecting 305 normal subjects , 300 patients with polyps , and 116 colorectal cancers from the cohort . All the 2652 polyps were linked to national cancer registry to ascertain 25 invasive carcinomas after polypectomy . For the five-state model associated with adenoma size , dwelling times of small ( 0.6–1 cm ) and large adenoma ( > 1 cm ) are 7.75 and 5.27 years for the model without considering de novo , and 17.48 and 15.90 years for the model taking de novo carcinoma into account . Similar findings are observed for the model associated with histological type . The estimated proportions of de novo carcinoma are 31.87 % from the model by adenoma size and 27.81 % from the model by histological type . Compared to size less than 5 mm , patients with adenoma size between 6 and 10 mm and patients with adenoma size larger than 1 cm have 2.17-fold ( 0.67–10.74 ) and 4.25-fold ( 1.23–14.70 ) , respectively , for the risk of malignant transformation . There are similar findings for the model by histological type . The estimates of overall efficacy of colonoscopy in reducing CRC is 73 % for the model allowing for de novo carcinoma and 88 % for the model without considering de novo carcinoma theory . The efficacy of diminutive adenoma and small adenoma increases with follow-up years , whereas the efficacy of large adenoma decreases with follow-up years . In conclusion , about 30 % of cancers arising from de novo sequence are demonstrated . This finding , together with the adenoma – carcinoma sequence associated with adenoma size and histological type , is important for the estimation of dwelling times , the efficacy of colonoscopy , and the surveillance of polyp after polypectomy 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 . ) Introduction . The implementation of mass colorectal cancer ( CRC ) screening is a public health priority . Population participation is fundamental for the success of CRC screening as for any cancer screening program . The preferences of the population may influence their likelihood of participation . Objectives . The authors sought to elicit population preferences for CRC screening test characteristics to improve the design of CRC screening campaigns . Methods . A discrete choice experiment was used . Question naires were compiled with a set of pairs of hypothetical CRC screening scenarios . The survey was conducted by mail from June 2006 to October 2006 on a representative sample of 2000 inhabitants , aged 50 to 74 years from the northwest of France , who were r and omly selected from electoral lists . Question naires were sent to 2000 individuals , each of whom made 3 or 4 discrete choices between hypothetical tests that differed in 7 attributes : how screening is offered , process , sensitivity , rate of unnecessary colonoscopy , expected mortality reduction , method of screening test result transmission , and cost . Results . Complete responses were received from 656 individuals ( 32.8 % ) . The attributes that influenced population preferences included expected mortality reduction , sensitivity , cost , and process . Participants from high social classes were particularly influenced by sensitivity . Conclusions . The results demonstrate that the discrete choice experiment provides information on patient preferences for CRC screening : improving screening program effectiveness , for instance , by improving test sensitivity ( the most valued attribute ) would increase satisfaction among the general population with regard to CRC screening programs . Additional studies are required to study how patient preferences actually affect adherence to regular screening programs PURPOSE Colonoscopic surveillance is recommended for individuals with familial colorectal cancer ( CRC ) . However , the appropriate screening interval has not yet been determined . The aim of this r and omized trial was to compare a 3-year with a 6-year screening interval . PATIENTS AND METHODS Individuals between ages 45 and 65 years with one first-degree relative with CRC age < 50 years or two first-degree relatives with CRC were selected . Patients with zero to two adenomas at baseline were r and omly assigned to one of two groups : group A ( colonoscopy at 6 years ) or group B ( colonoscopy at 3 and 6 years ) . The primary outcome measure was advanced adenomatous polyps ( AAPs ) . Risk factors studied included sex , age , type of family history , and baseline endoscopic findings . RESULTS A total of 528 patients were r and omly assigned ( group A , n = 262 ; group B , n = 266 ) . Intention-to-treat analysis showed no significant difference in the proportion of patients with AAPs at the first follow-up examination at 6 years in group A ( 6.9 % ) versus 3 years in group B ( 3.5 % ) . Also , the proportion of patients with AAPs at the final follow-up examination at 6 years in group A ( 6.9 % ) versus 6 years in group B ( 3.4 % ) was not significantly different . Only AAPs at baseline was a significant predictor for the presence of AAPs at first follow-up . After correction for the difference in AAPs at baseline , differences between the groups in the rate of AAPs at first follow-up and at the final examination were statistically significant . CONCLUSION In view of the relatively low rate of AAPs at 6 years and the absence of CRC in group A , we consider a 6-year surveillance interval appropriate . A surveillance interval of 3 years might be considered in patients with AAPs and patients with ≥ three adenomas OBJECTIVES : Fecal occult blood testing ( FOBT ) and sigmoidoscopy are proven to decrease colorectal cancer ( CRC ) incidence and mortality . Sigmoidoscopy 's benefit is limited to the distal colon . Observational data are conflicting regarding the degree to which colonoscopy affords protection against proximal CRC . Our aim was to explore the comparative effectiveness and cost-effectiveness of colonoscopy vs. sigmoidoscopy and alternative CRC screening strategies in light of the latest published data . METHODS : We performed a contemporary cost-utility analysis using a Markov model vali date d against data from r and omized controlled trials of FOBT and sigmoidoscopy .  Persons at average CRC risk within the general US population were modeled . Screening strategies included those recommended by the United States ( US ) Preventive Services Task Force , including colonoscopy every 10 years ( COLO ) , flexible sigmoidoscopy every 5 years ( FS ) , annual fecal occult blood testing , annual fecal immunochemical testing ( FIT ) , and the combination FS/FIT . The main outcome measures were quality -adjusted life-years ( QALYs ) and costs . RESULTS : In the base case , FIT dominated other strategies . The advantage of FIT over FS and COLO was contingent on rates of uptake and adherence that are well above current US rates . Compared with FIT , FS and COLO both cost < $ 50,000/QALY gained when FIT per-cycle adherence was < 50 % . COLO cost $ 56,800/QALY gained vs. FS in the base case . COLO cost < $ 100,000/QALY gained vs. FS when COLO yielded a relative risk of proximal CRC of < 0.5 vs. no screening . In probabilistic analyses , COLO was cost-effective vs. FS at a willingness-to-pay threshold of $ 100,000/QALY gained in 84 % of iterations . CONCLUSIONS : Screening colonoscopy may be cost-effective compared with FIT and sigmoidoscopy , depending on the relative rates of screening uptake and adherence and the protective benefit of colonoscopy in the proximal colon . Colonoscopy 's cost-effectiveness compared with sigmoidoscopy is contingent on the ability to deliver ∼50 % protection against CRC in the proximal colon BACKGROUND AND AIMS The link between adenoma characteristics at baseline colonoscopy and adenoma recurrence is poorly understood . We assessed whether the number , size , location , or histology of resected adenomas was related to the probability of recurrence of advanced lesions . METHODS Analyses were based on 1287 men and women in the wheat bran fiber ( WBF ) study , a r and omized , double-blind trial of  WBF as a means of decreasing the probability of adenoma recurrence over a period of 3 years . Multiple logistic regression was used to calculate odds ratios ( ORs ) and 95 % confidence intervals ( CIs ) . RESULTS Recurrence of advanced adenomas ( > 1 cm or tubulovillous/villous histology ) was higher among individuals with adenomas > 1 cm compared with those with adenomas < 0.5 cm ( OR , 2.69 ; 95 % CI , 1.34 - 5.42 ) and among those with proximal than those with distal adenomas ( OR , 1.65 ; 95 % CI , 1.02 - 2.67 ) . No association was observed for adenoma number or histology . A shift in location from the distal colon and rectum at baseline ( 54.6 % ) to more proximal recurrent adenomas ( 45.2 % ) , including advanced lesions ( 42.8 % ) , was observed . CONCLUSIONS Large or proximally located adenomas are important indicators of recurrence of advanced lesions . Because most recurrences were detected in the proximal colon , careful surveillance of this area is warranted Background : Colonoscopic screening is recommended for first-degree relatives of patients diagnosed with colorectal cancer ( CRC ) or colorectal adenomatous polyps ( CAP ) before the age of 60 years . This has the potential to reduce CRC-related morbidity and mortality , but uptake is currently inadequate . Methods : The aim of the study was to compare the effectiveness of st and ard information versus a nurse-led tailored intervention design ed to promote uptake of  colonoscopy screening by siblings of CRC or CAP patients . A r and omized controlled trial was conducted . Digestive surgeons and gastroenterologists recruited index patients who developed CRC or CAP before the age of 60 years . All index patients received st and ard screening information for their siblings , in keeping with current guidelines . Central ly computerized r and omization of index patients result ed in allocating all their siblings to the same group , intervention or control . The tailored intervention targeted the index patient first , to help them convey information to their siblings . The nurse then provided the siblings with tailored information based on their answers to a self- question naire which explored health behaviors , derived from psychosocial models of prevention . Then the siblings were given a personalized information leaf 
    Output:
    
RESULTS Based on the evidence , the Consensus Group was able to strongly recommend CRC screening for all individuals with an FH of CRC or documented adenoma .
Colonoscopy is suggested ( recommended in individuals with ≥2 first-degree relatives [ FDRs ] ) , with fecal immunochemical test as an alternative .
The elevated risk associated with an FH of ≥1 FDRs with CRC or documented advanced adenoma suggests initiating screening at a younger age ( eg , 40 - 50 years or 10 years younger than age of diagnosis of FDR ) .
It is suggested that individuals with an FH of ≥1 second-degree relatives only , or of nonadvanced adenoma or polyp of unknown histology , be screened according to average-risk guidelines .
The increased risk of CRC associated with an FH of CRC or advanced adenoma warrants more intense screening for CRC .