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Incremental benefits of screening colonoscopy over sigmoidoscopy in average-risk populations: a model-driven analysis.

ABSTRACT: Screening colonoscopy and flexible sigmoidoscopy (FSG) reduce the risk of colorectal cancer (CRC), but the magnitude and duration of protection, particularly against right-sided cancer, remain uncertain. We computed the incremental benefit of colonoscopy over FSG using a validated mathematical model, which reflects colorectal neoplasia growth characteristics while allowing uncertainty in endoscopic detection and removal of adenomas.We calibrated models of CRC incidence within a multistage clonal expansion framework to data from: (1) San Francisco-Oakland SEER registry (reference population) and (2) FSG long-term follow-up data from 50,757 individuals after a negative FSG in the Kaiser Permanente system. We compared the residual CRC risks after FSG with full-length colonoscopy.Our model mirrors trial data with 10-year CRC risk reductions after FSG screening at age 50 years of approximately one-third; the optimal age for a 'once-only' FSG exam was between ages 50 and 60 years; and the greater benefit was for men compared with women. There were considerable incremental gains in reduction in CRC risk by colonoscopy compared with FSG with the greatest benefit for screening colonoscopy at age 50 years. These results held up against lowering the right-sided adenoma detection sensitivity by 30%, as well as reducing the curative efficacy of polypectomy throughout the colon.Mathematical modeling of CRC screening, which takes account of important aspects of tumor biology, demonstrates superior risk reductions by colonoscopy over FSG. Our predictions provide further rationale for recommending screening colonoscopy in average-risk populations before the age of 60.

SUBMITTER: Jeon J

PROVIDER: S-EPMC4646080 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature

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Incremental benefits of screening colonoscopy over sigmoidoscopy in average-risk populations: a model-driven analysis.

Jeon Jihyoun J Meza Rafael R Hazelton William D WD Renehan Andrew G AG Luebeck E Georg EG

Cancer causes & control : CCC 20150318 6

<h4>Purpose</h4>Screening colonoscopy and flexible sigmoidoscopy (FSG) reduce the risk of colorectal cancer (CRC), but the magnitude and duration of protection, particularly against right-sided cancer, remain uncertain. We computed the incremental benefit of colonoscopy over FSG using a validated mathematical model, which reflects colorectal neoplasia growth characteristics while allowing uncertainty in endoscopic detection and removal of adenomas.<h4>Methods</h4>We calibrated models of CRC inci ...[more]

PMID: 25783458

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Project description:ImportanceRandomized clinical screening trials have shown that sigmoidoscopy screening reduces colorectal cancer (CRC) incidence and mortality. Colonoscopy has largely replaced sigmoidoscopy for CRC screening, but long-term results from randomized trials on colonoscopy screening are still lacking.ObjectiveTo estimate the additional screening benefit of colonoscopy compared with sigmoidoscopy.Design, setting, and participantsThis comparative effectiveness simulation study pooled data on 358 204 men and women randomly assigned to sigmoidoscopy screening or usual care in 4 randomized sigmoidoscopy screening trials conducted in Norway, Italy, the US, and UK with inclusion periods in the years 1993 to 2001. The primary analysis of the study was conducted from January 19 to December 30, 2021.InterventionInvitation to endoscopic screening.Main outcomes and measuresPrimary outcomes were CRC incidence and mortality. Using pooled 15-year follow-up data, colonoscopy screening effectiveness was estimated assuming that the efficacy of colonoscopy in the proximal colon was similar to that observed in the distal colon in the sigmoidoscopy screening trials. The simulation model was validated using data from Norwegian participants in a colonoscopy screening trial.ResultsThis analysis included 358 204 individuals (181 971 women [51%]) aged 55 to 64 years at inclusion with a median follow-up time ranging from 15 to 17 years. Compared with usual care, colonoscopy prevented an estimated 50 (95% CI, 42-58) CRC cases per 100 000 person-years, corresponding to 30% incidence reduction (rate ratio, 0.70 [95% CI, 0.66-0.75]), and prevented an estimated 15 (95% CI, 11-19) CRC deaths per 100 000 person-years, corresponding to 32% mortality reduction (rate ratio, 0.68 [95% CI, 0.61-0.76]). The additional benefit of colonoscopy screening compared with sigmoidoscopy was 12 (95% CI, 10-14) fewer CRC cases and 4 (95% CI, 3-5) fewer CRC deaths per 100 000 person-years, corresponding to percentage point reductions of 6.9 (95% CI, 6.0-7.9) for CRC incidence and 7.6 (95% CI, 5.7-9.6) for CRC mortality. The number needed to switch from sigmoidoscopy to colonoscopy screening was 560 (95% CI, 486-661) to prevent 1 CRC case and 1611 (95% CI, 1275-2188) to prevent 1 CRC death.Conclusions and relevanceThe findings of this comparative effectiveness study assessing long-term follow-up after CRC screening suggest that there was an additional preventive effect on CRC incidence and mortality associated with colonoscopy screening compared with sigmoidoscopy screening, but the additional preventive effect was less than what was achieved by introducing sigmoidoscopy screening where no screening existed. The results probably represent the upper limit of what may be achieved with colonoscopy screening compared with sigmoidoscopy screening.

Project description:OBJECTIVE:To estimate benefits and harms of different colorectal cancer screening strategies, stratified by (baseline) 15-year colorectal cancer risk. DESIGN:Microsimulation modelling study using MIcrosimulation SCreening ANalysis-Colon (MISCAN-Colon). SETTING:A parallel guideline committee (BMJ Rapid Recommendations) defined the time frame and screening interventions, including selection of outcome measures. POPULATION:Norwegian men and women aged 50-79 years with varying 15-year colorectal cancer risk (1-7%). COMPARISONS:Four screening strategies were compared with no screening: biennial or annual faecal immunochemical test (FIT) or single sigmoidoscopy or colonoscopy at 100% adherence. MAIN OUTCOME MEASURES:Colorectal cancer mortality and incidence, burdens, and harms over 15 years of follow-up. The certainty of the evidence was assessed using the GRADE approach. RESULTS:Over 15 years of follow-up, screening individuals aged 50-79 at 3% risk of colorectal cancer with annual FIT or single colonoscopy reduced colorectal cancer mortality by 6 per 1000 individuals. Single sigmoidoscopy and biennial FIT reduced it by 5 per 1000 individuals. Colonoscopy, sigmoidoscopy, and annual FIT reduced colorectal cancer incidence by 10, 8, and 4 per 1000 individuals, respectively. The estimated incidence reduction for biennial FIT was 1 per 1000 individuals. Serious harms were estimated to be between 3 per 1000 (biennial FIT) and 5 per 1000 individuals (colonoscopy); harms increased with older age. The absolute benefits of screening increased with increasing colorectal cancer risk, while harms were less affected by baseline risk. Results were sensitive to the setting defined by the guideline panel. Because of uncertainty associated with modelling assumptions, we applied a GRADE rating of low certainty evidence to all estimates. CONCLUSIONS:Over a 15 year period, all screening strategies may reduce colorectal cancer mortality to a similar extent. Colonoscopy and sigmoidoscopy may also reduce colorectal cancer incidence, while FIT shows a smaller incidence reduction. Harms are rare and of similar magnitude for all screening strategies.

Project description:IntroductionPhysical harm from Colorectal Cancer Screening tends to be inadequately measured and reported in clinical trials. Also, studies of ongoing Colorectal Cancer Screening programs have found more frequent and severe physical harm from screening procedures, e.g., bleeding and perforation, than reported in previous trials. Therefore, the objectives of the study were to systematically review the evidence on the risk of bleeding and perforation in Colorectal Cancer Screening.DesignSystematic review with descriptive statistics and random-effects meta-analyses.MethodsWe systematically searched five databases for studies investigating physical harms related to Colorectal Cancer Screening. We assessed the internal and the external validity using the ROBINS-I tool and the GRADE approach. Harm estimates was calculated using mixed Poisson regression models in random-effect meta-analyses.ResultsWe included 89 studies. Reporting and measurement of harms was inadequate in most studies. In effect, the risk of bias was critical in 97.3% and serious in 98.3% of studies. All GRADE ratings were very low. Based on severe findings with not-critical risk of bias and 30 days follow-up, the risk of bleedings per 100,000 people screened were 8 [2;24] for sigmoidoscopy, 229 [129;408] for colonoscopy following fecal immunochemical test, 68 [39;118] for once-only colonoscopy, and 698 [443;1045] for colonoscopy following any screening tests. The risk of perforations was 88 [56;138] for colonoscopy following fecal immunochemical test and 53 [25;112] for once-only colonoscopy. There were no findings within the subcategory severe perforation with long-term follow-up for colonoscopy following any screening tests and sigmoidoscopy.DiscussionHarm estimates varied widely across studies, reporting and measurement of harms was mostly inadequate, and the risk of bias and GRADE ratings were very poor, collectively leading to underestimation of harm. In effect, we consider our estimates of perforation and bleeding as conservative, highlighting the need for better reporting and measurement in future studies.Trial registrationPROSPERO registration number: CRD42017058844.

Project description:BackgroundAlthough split-dose bowel regimen is recommended in colon cancer screening and surveillance guidelines, implementation in clinical practice has seemingly lagged because of concerns of patient compliance.ObjectivesTo assess patient compliance with the split-dose bowel regimen and assess patient- and preparation process-related factors associated with compliance and bowel preparation adequacy.DesignProspective survey cohort.SettingTertiary care setting.PatientsAverage-risk patients undergoing colonoscopy for colorectal cancer screening between August 2011 and January 2013.Main outcome measurementsSplit-dose bowel regimen patient-reported compliance and bowel preparation adequacy with the Boston Bowel Preparation Scale score.ResultsSurveys and Boston Bowel Preparation Scale score data were completed in 462 participants; 15.4% were noncompliant with the split-dose bowel regimen, and suboptimal bowel preparation (score <5) was reported in 16% of all procedures. White (P = .009) and married (P = .01) subjects were least likely to be noncompliant, whereas Hispanic subjects and those who reported incomes of US$75,000 or less were most likely to be noncompliant (P = .004). Participants who were noncompliant with split-dosing were less likely to follow the other laxative instructions and more likely to have their colonoscopy appointment before 10:30 am. Compliance differed by bowel preparation type (P = .003, χ(2) test), with those who used MiraLAX showing the highest compliance, followed by polyethylene glycol electrolyte solution and other bowel preparations. Noncompliance with split-dose bowel preparation (odds ratio 6.7; 95% confidence interval, 3.2-14.2) was the strongest predictor of suboptimal bowel preparation.LimitationsPatient self-report, performed at tertiary care center.ConclusionsOverall, 1 in 7 patients do not comply with a split-dose bowel regimen. Ensuring compliance with the split-dose bowel regimen will reduce the risk of a suboptimal bowel preparation.

Project description:BackgroundFlexible sigmoidoscopy and colonoscopy are recommended screening options for colorectal cancer (CRC). Despite colonoscopy being offered for CRC screening in Germany, the uptake of this offer has been very limited.ObjectiveThe objective of this study was to assess the potential for increasing use of endoscopic CRC screening and the detection of advanced colorectal neoplasms by offering the choice between use of flexible sigmoidoscopy and colonoscopy.MethodsThe DARIO study includes a cross-sectional study (part I), followed by a prospective 2-arm randomized controlled intervention trial (part II) with an associated biobank study (part III). Participation is possible in part I of the DARIO study only, parts I and II, or all 3 study parts. After obtaining informed consent from the municipalities, 12,000 people, aged 50-54 years, from the Rhine-Neckar region in Germany were randomly selected from residential lists of the responsible population registries and invited to complete a standardized questionnaire to investigate the nature, frequency, timing, and results of previous CRC screening and eventual diagnostic colonoscopies. In study part II participants from study part I with no colonoscopy in the preceding 5 years are randomized into 2 arms: arm A offering screening colonoscopy only, and arm B offering both options, either screening colonoscopy or screening sigmoidoscopy. The primary endpoint is the proportion of participants in whom colorectal neoplasms >0.5 cm are detected and removed at screening endoscopy. The secondary endpoints are the detection rate of any neoplasm and use of any endoscopic screening. Part III of the study will use samples from participants in study part II to construct a liquid and tissue biobank for the evaluation of less invasive methods of early detection of colon cancer and for the more detailed characterization of the detected neoplasms. Blood, urine, stool, and saliva samples are taken before the endoscopy. Tissue samples are obtained from the neoplasms removed during endoscopy.ResultsA total of 10,568 from 12,000 randomly selected women and men aged 50-54 years living in the Rhine-Neckar-Region of Germany have been invited for participation. The remaining 1432 (11.93%) could not be invited because they reached the age of 55 at the time of contact. Of those invited, 2785/10,568 (26.35%) participated in study part I; 53.60% (1493/2785) of these participants were female. Study parts II and III are ongoing.ConclusionsThis study will answer the question if alternative offers of either screening sigmoidoscopy or screening colonoscopy will increase utilization and effectiveness of endoscopic CRC screening compared with an exclusive offer of screening colonoscopy. In addition, alternative noninvasive screening tests will be developed and validated.Trial registrationGerman Clinical Trials Register DRKS00018932; https://www.drks.de/drks_web/navigate.do? navigationId=trial.HTML&TRIAL_ID=DRKS00018932.International registered report identifier (irrid)DERR1-10.2196/17516.

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Incremental benefits of screening colonoscopy over sigmoidoscopy in average-risk populations: a model-driven analysis.

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Incremental benefits of screening colonoscopy over sigmoidoscopy in average-risk populations: a model-driven analysis.

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