Sigmoidoscopy Screening Research Articles

Annals for Educators - November 2022

Annals for Educators - November 2022

15-Year Benefits of Sigmoidoscopy Screening on Colorectal Cancer Incidence and Mortality : A Pooled Analysis of Randomized Trials.

The effectiveness of screening for colorectal cancer (CRC) by sex and age in randomized trials is uncertain. To evaluate the 15-year effect of sigmoidoscopy screening on CRC incidence and mortality. Pooled analysis of 4 large-scale randomized trials of sigmoidoscopy screening. Norway, the United States, the United Kingdom, and Italy. Women and men aged 55 to 64 years at enrollment. Sigmoidoscopy screening. Primary end points were cumulative incidence rate ratio (IRR) and mortality rate ratio (MRR) and rate differences after 15 years of follow-up comparing screening versus usual care in intention-to-treat analyses. Stratified analyses were done by sex, cancer site, and age at screening. Analyses comprised 274952 persons (50.7% women), 137493 in the screening and 137459 in the usual care group. Screening attendance was 58% to 84%. After 15 years, the rate difference for CRC incidence was 0.51 cases (95% CI, 0.40 to 0.63 cases) per 100 persons and the IRR was 0.79 (CI, 0.75 to 0.83). The rate difference for CRC mortality was 0.13 deaths (CI, 0.07 to 0.19 deaths) per 100 persons, and the MRR was 0.80 (CI, 0.72 to 0.88). Women had less benefit from screening than men for CRC incidence (IRR for women, 0.84 [CI, 0.77 to 0.91]; IRR for men, 0.75 [CI, 0.70 to 0.81]; P= 0.032 for difference) and mortality (MRR for women, 0.91 [CI, 0.77 to 1.17]; MRR for men, 0.73 [CI, 0.64 to 0.83]; P= 0.025 for difference). There was no statistically significant difference in screening effect between persons aged 55 to 59 years and those aged 60 to 64 years. Data from the U.K. trial were less granular because of privacy regulations. This pooled analysis of all large randomized trials of sigmoidoscopy screening demonstrates a significant and sustained effect of sigmoidoscopy on CRC incidence and mortality for 15 years. Health Fund of South-East Norway.

Type and Severity of Mental Illness and Participation in Colorectal Cancer Screening

The effectiveness of colorectal cancer screening programs depends on the participation rate. This study examined the association between type and severity of mental illness and colorectal cancer screening participation. Between 2012 and 2017, a total of 46,919 individuals were invited to sigmoidoscopy screening in Norway, and 70,019 were invited to fecal immunochemical testing. In 2022, logistic regression was used to evaluate the association between the use of antipsychotics, anxiolytics, hypnotics, and antidepressants in the year preceding the screening invitation and screening participation, adjusted for demographic and socioeconomic factors. Defined daily doses of individual drugs were used to assess dose‒response relationships. Overall, 19.2% (24.8% of women, 13.4% of men) of all invitees used at least 1 psychotropic medication. Nonparticipation in the 2 arms combined was associated with the use of anxiolytics (60.7% in users vs 43.2% in nonusers; OR=1.53; 95% CI=1.45, 1.62) and antipsychotics (64.3% vs 43.8%; OR=1.41; 95% CI=1.30, 1.53) and increased with higher doses for both drugs. Hypnotics and antidepressants were only weakly associated with nonparticipation in higher doses. Participation rates were 57.3%, 52.3%, 42.9%, and 35.4% in those prescribed 0, 1, 2, and 3-4 classes of psychotropic medications, respectively. The associations between the use of psychotropic medications and nonparticipation were similar for the 2 screening tests. These findings show significant disparities in colorectal cancer screening participation for individuals with mental illness, independent of the screening method. Moreover, screening participation varied depending on the type and severity of mental illness. Targeted interventions are warranted to ensure that people with mental illness are supported to access the benefits of colorectal cancer screening.

The impact of driving time on participation in colorectal cancer screening with sigmoidoscopy and faecal immunochemical blood test

BackgroundHigh participation rates are important for a colorectal cancer (CRC) screening programme to be effective. Having a long travelling distance to screening centres may impede participation. MethodsWe analysed the association between driving time from home address to screening centre and participation among individuals invited to screening with faecal immunochemical test (FIT) (n = 68,624) or sigmoidoscopy (n = 46,076) in a randomized trial in Norway in 2012–17. Two screening centres were involved. We fitted multiple logistic regression models, adjusted for demographic, socioeconomic and health characteristics, and reported odds ratios (OR) with 95% confidence intervals (CI). ResultsParticipation rates were 58.9 % (n = 40,445) for FIT and 51.9 % (n = 23,911) for sigmoidoscopy. In sigmoidoscopy, participation was 56.9 % and 47.9 % in those living < 20 and > 60 min by car from the screening centres, respectively. For each 10 min driving time increase, OR for participating in sigmoidoscopy screening was 0.93 (95 % CI 0.91–0.95). There was a significant difference between the two screening centres (p-value for heterogeneity <0.001). Participation in FIT screening were 61.2 % and 57.1 % in those with < 20 and > 60 min driving time, respectively, and the OR was 0.98 (95 % CI 0.96–0.99) for each 10 min increase (heterogeneity between screening methods, P-value <0.001). Among those with a positive FIT, compliance to colonoscopy was higher in those living < 20 compared to > 60 min from the centres (95.1 % vs. 92.9 %, respectively, OR 0.86; 95 % CI 0.77–0.93 for each 10 min increase). ConclusionsDriving time to screening centre was a significant predictor of participation, mainly in sigmoidoscopy. There were local differences in the impact of driving time on participation. Driving time also affected compliance to colonoscopy after a positive FIT. When planning a CRC screening programme, one should consider offering people living far from screening sites special assistance to facilitate their participation.

Age at Initiation of Lower Gastrointestinal Endoscopy and Colorectal Cancer Risk Among US Women

In the past 4 years, the American Cancer Society and the US Preventive Services Task Force updated recommendations to initiate colorectal cancer (CRC) screening at 45 years of age to address the increasing incidence of CRC among adults younger than 50 years. However, empirical evidence evaluating the potential benefits of screening in younger populations is scant. To examine the association between endoscopy initiation at different ages and risk of CRC among US women. This prospective cohort study used data from the Nurses' Health Study II, which included US female health professionals followed up from 1991 through 2017. Data analysis was performed from August 2020 to June 2021. Age at initiation of sigmoidoscopy or colonoscopy for screening (routine screening or because of family history) or symptoms. Incident CRC, confirmed by medical records, pathology reports, and the National Death Index. Cumulative incidence of CRC in each group was estimated with age as the time scale, and the absolute risk reduction associated with endoscopy initiation at different ages through 60 years was calculated. Cox proportional hazards regression was used to calculate hazard ratios (HRs) and 95% CIs, stratified by age and calendar year of questionnaire cycle and adjusted for CRC risk factors in the multivariable models. Among 111 801 women aged 26 to 46 years (median, 36 years) at enrollment, 519 incident CRC cases were documented over 26 years, encompassing 2 509 358 person-years of follow-up. In the multivariable analysis, compared with no endoscopy, undergoing endoscopy was associated with a significantly lower risk of incident CRC for age at initiation before 45 years (HR, 0.37; 95% CI, 0.26-0.53), 45 to 49 years (HR, 0.43; 95% CI, 0.29-0.62), 50 to 54 years (HR, 0.47; 95% CI, 0.35-0.62), and 55 years or older (HR, 0.46; 95% CI, 0.30-0.69). The absolute reduction in the estimated cumulative incidence of CRC through 60 years of age was 72 per 100 000 persons for initiation of endoscopy at 45 to 49 years of age vs 50 to 54 years of age. Compared with no endoscopy, initiation of endoscopy before 50 years of age was also associated with a reduced risk of CRC diagnosed before 55 years of age (<45 years: HR, 0.45 [95% CI, 0.29-0.70]; 45-49 years: HR, 0.43 [95% CI, 0.24-0.76]). In this cohort study, compared with no endoscopy, initiation of endoscopy before 50 years of age was associated with a reduced risk of CRC, including CRC diagnosed before 55 years of age. Screening before 50 years of age was associated with greater absolute reduction in CRC risk compared with initiation of CRC screening at 50 years of age or later.

Is inguinal hernia associated with an increased risk of colon cancer? A systematic review and meta-analysis.

The presence of an inguinal hernia has been associated with an increased risk of identifying colon cancer, and therefore colonoscopy is recommended prior to inguinal hernia repair. However, the evidence on the association between the presence of an inguinal hernia and colon cancer is conflicting and uncertain. We performed a systematic review and meta-analysis to synthesize all available evidence on this topic. A comprehensive search of PubMed and EMBASE was performed. Any comparative study (case-control or cohort study) comparing the rate of colon cancer detection in patients with and without inguinal hernias who underwent screening colonoscopy or flexible sigmoidoscopy was eligible for inclusion. Data were extracted and pooled under a random effects model. The initial search identified 692 references, of which 4 comparative studies (1462 patients) met the inclusion criteria. The overall risk of bias in the included studies was low. Pooled results showed a statistically non-significant difference in the incidence of detection of colon cancer, with patients with inguinal hernia having a 1.26 times increased likelihood of colon cancer diagnosis compared with patients without inguinal hernia (odds ratio (OR) 1.26; 95% confidence interval (CI) 0.63-2.51; P = 0.51). Although patients with inguinal hernia were also 1.23 times more likely to be diagnosed with colon polyps compared to patients without inguinal hernia, this difference was statistically non-significant (OR 1.23; 95% CI 0.94-1.60; P = 0.12). The findings from this first systematic review and meta-analysis show that there is no difference in the incidence of either colon cancer or colon polyps in patients presenting with inguinal hernias compared to those without. Nevertheless, larger prospective studies are needed to further investigate the relationship between the risk of colon cancer or polyps and the presence of inguinal hernia.

Microsimulation Model for Prevention and Intervention of Coloretal Cancer in China (MIMIC-CRC): Development, Calibration, Validation, and Application.

IntroductionA microsimulation model provides important references for decision-making regarding colorectal cancer (CRC) prevention strategies, yet such a well-validated model is scarce in China.MethodsWe comprehensively introduce the development of MIcrosimulation Model for the prevention and Intervention of Colorectal Cancer in China (MIMIC-CRC). The MIMIC-CRC was first constructed to simulate the natural history of CRC based on the adenoma-carcinoma pathway. The parameters were calibrated and validated using data from population-based cancer registry data and CRC screening programs. Furthermore, to assess the model’s external validity, we compared the model-derived results to outcome patterns of a sigmoidoscopy screening trial in the UK [UK Flexible Sigmoidoscopy Screening (UKFSS) trial]. Finally, we evaluated the application potential of the MIMIC-CRC model in CRC screening by comparing the 8 different strategies.ResultsWe found that most of the model-predicted colorectal lesion prevalence was within the 95% CIs of observed prevalence in a large population-based CRC screening program in China. In addition, model-predicted sex- and age-specific CRC incidence and mortality were equivalent to the registry-based data. The hazard ratios of model-estimated CRC-related incidence and mortality for sigmoidoscopy screening compared to no screening were 0.60 and 0.51, respectively, which were comparable to the reported results of the UKFSS trial. Moreover, we found that all 8 strategies could reduce CRC incidence and mortality compared to no screening.ConclusionsThe well-calibrated and validated MIMIC-CRC model may represent a valid tool to assess the comparative effectiveness of CRC screening strategies and will be useful for further decision-making to CRC prevention.

Characteristics of nonparticipants in a randomised colorectal cancer screening trial comparing sigmoidoscopy and faecal immunochemical testing.

Public health systems should guarantee universal access to health care services, including cancer screening. We assessed whether certain population subgroups were underrepresented among participants in colorectal cancer screening with sigmoidoscopy and faecal immunochemical testing (FIT). Between 2012 and 2019, about 140 000 individuals aged 50 to 74 years were randomly invited to once‐only sigmoidoscopy or first round of FIT screening. Our study included 46 919 individuals invited to sigmoidoscopy and 70 019 to FIT between 2012 and 2017. We used logistic regression models to evaluate if demographic and socioeconomic factors and use of certain drugs were associated with participation. Twenty‐four thousand one hundred and fifty‐nine (51.5%) individuals attended sigmoidoscopy and 40 931 (58.5%) FIT screening. Male gender, young age, low education and income, being retired or unemployed, living alone, being an immigrant, long driving time to screening centre, and use of antidiabetic and psychotropic drugs were associated with low participation in both screening groups. Many of these factors also predicted low acceptance of colonoscopy after positive FIT. While male gender, young age and living alone were more strongly associated with nonparticipation in FIT than sigmoidoscopy, low education and income, being retired or immigrant and long driving time were more strongly associated with nonparticipation in sigmoidoscopy than FIT. In conclusion, participation was lower in sigmoidoscopy than FIT. Predictors of nonparticipation were similar between arms. However, low socioeconomic status, being an immigrant and long driving time affected participation more in sigmoidoscopy screening, suggesting that FIT may guarantee more equal access to screening services than sigmoidoscopy.

Invitation to a single FS screening vs. usual care reduced colorectal cancer mortality and incidence at >15 y.

Senore C, Riggi E, Armaroli P, et al. Long-term follow-up of the Italian flexible sigmoidoscopy screening trial. Ann Intern Med. 2022;175:36-45. 34748376.

Preferences for colorectal cancer screening of physicians and individuals at average risk in the United States: A discrete choice experiment.

60 Background: Several colorectal cancer (CRC) screening options are considered in guidelines for individuals at average-risk (IAR). These options differ in aspects such as invasiveness, recommended frequency, and precision that need to be compared and weighed. This study elicited and compared the relative importance that physicians and IAR place on these screening aspects. Methods: Primary care physicians [PCPs] and gastroenterologists [GIs] who recommended/performed ≥1 screening one month prior to study and adult IAR completed a discrete choice experiment (DCE). Participants repeatedly chose between screening tests described by type of test, frequency, true-positive (TP), true-negative (TN), and adenoma TP (physicians only). The instrument was tested in qualitative (physicians: n=6; IAR: n=6) and quantitative pilots (physicians: n=100; IAR: n=202). A mixed logit model was used to estimate relative attribute importance (RAI) and predicted choice probabilities for colonoscopy, multi-target stool DNA (mt-sDNA), fecal immunochemical test (FIT), and methylated septin 9 (mSEPT9) blood test. Generalizability to the population was confirmed. Results: 1,249 IAR and 400 physicians participated. IAR were 46% male and the mean age was 58.9. Physicians were 79% male and their mean age was 53.4. Preferences were most affected by TP rates (IAR RAI=58%; physicians RAI=42%). Physicians also placed high importance (RAI=41%) on adenoma TP rates. TN rates (IAR RAI=33%; physician RAI=9%), frequency (IAR RAI=6%; physician RAI=2%) and type (IAR RAI=4%; physician RAI=6%) were less important. Despite both IAR and physicians placing most importance on precision, preferences for screening modalities differed. On average, physicians preferred colonoscopy, while IAR preferred mt-sDNA over colonoscopy (p&lt;0.001). Both preferred mt-sDNA and colonoscopy over FIT (p&lt;0.001), with a mSEPT9 blood test being least preferred (p&lt;0.001). Preferences of IAR were heterogeneous with individuals who underwent colonoscopy or sigmoidoscopy screening preferring colonoscopy and the rest preferring mt-sDNA (p&lt;0.001). Conclusions: While both GI and PCPs overwhelmingly preferred colonoscopy, preferences of IAR were heterogenous, with mt-sDNA being preferred on average other modalities. Offering choices in addition to colonoscopy could improve screening uptake. [Table: see text]

Additional offer of sigmoidoscopy in colorectal cancer screening in Germany: rationale and protocol of the decision-analytic modelling approach in the SIGMO study

IntroductionIn Germany, statutory insured persons are entitled to a stool test (faecal immunochemical test (FIT)) or colonoscopy for colorectal cancer (CRC) screening, depending on age and sex, yet participation rates...

Long-Term Follow-up of the Italian Flexible Sigmoidoscopy Screening Trial.

Recent reports showed that the protective effect of flexible sigmoidoscopy (FS) screening was maintained up to17 years, although differences were reported by sex. To assess long-term reduction of colorectal cancer (CRC) incidence and mortality after a single FS screening. Parallel randomized controlled trial. (ISRCTN registry number: 27814061). 6 centers in Italy. Persons aged 55 to 64 years expressing interest in having FS screening if invited, recruited from 1995 to 1999 and followed until 2012 (incidence) and 2014 to 2016 (mortality). Eligible persons were randomly assigned (1:1 ratio) to either the once-only FS screening group or control (usual care) group. Incidence and mortality rate ratios (RRs) and rate differences. A total of 34272 persons (17136 in each group) were included in the analysis; 9911 participants had screening in the intervention group. Median follow-up was 15.4 years for incidence and 18.8 years for mortality. Incidence of CRC was reduced by 19% (RR, 0.81 [95% CI, 0.71 to 0.93]) in the intention-to-treat (ITT) analysis, comparing the intervention with the control group, and by 33% (RR, 0.67 [CI, 0.56 to 0.81]) in the per protocol (PP) analysis, comparing participants screened in the intervention group with the control persons. Colorectal cancer mortality was reduced by 22% (RR, 0.78 [CI, 0.61 to 0.98]) in the ITT analysis and by 39% (RR, 0.61 [CI, 0.44 to 0.84]) in the PP analysis. Incidence of CRC was statistically significantly reduced among both men and women. Colorectal cancer mortality was statistically significantly reduced among men (ITT RR, 0.73 [CI, 0.54 to 0.97]) but not among women (ITT RR, 0.90 [CI, 0.59 to 1.37]). Self-selection of volunteers from the general population sample targeted for recruitment may limit generalizability. The strong protective effect of a single FS screening for CRC incidence and mortality was maintained up to 15 and 19 years, respectively. Italian Association for Cancer Research, Italian National Research Council, Istituto Oncologico Romagnolo, Fondo "E. Tempia," University of Milan, and Local Health Unit ASL-Torino.

Water immersion sigmoidoscopy versus standard insufflation for colorectal cancer screening: A cohort study.

Background:Although the efficacy of water-assisted colonoscopy is well established, the role of water immersion sigmoidoscopy (WIS) remains unclear. We compared WIS with carbon dioxide insufflation sigmoidoscopy (CO2S) on patient outcomes.Methods:We conducted an analysis of prospectively collected data from a single-center quality improvement program about patients undergoing unsedated screening sigmoidoscopy (WIS and CO2S) between May 2019 and January 2020. Outcomes studied included the following: Rates of severe pain <17% (score of ≥7 on a numeric rating scale of 0–10, and on a Likert scale), willingness to repeat the procedure without sedation, adequate bowel cleanliness >75% (proportion of Boston Bowel Preparation Scale score: 2–3) and adenoma detection rate (ADR).Results:In total, 234 patients (111 WIS; 123 CO2S) were included. All patients were aged 58 years and 58.9% were female; baseline characteristics were comparable between groups. There were no significant differences in rates of severe pain (WIS: 16.5%, CO2S: 13.8%; P = 0.586), willingness to repeat the unsedated procedure (WIS: 82.3%, CO2S: 84.5%; P = 0.713), adequate bowel cleanliness (WIS: 78.4%, CO2S: 78%, P = 0.999) or ADR (WIS: 25.2%, CO2S: 16.3%; P = 0.106) between groups. However, average procedure times were longer with WIS (9.06 min) compared to CO2S (6.45 min; P < 0.001). Overall, 29.6% of women reported that they would repeat sigmoidoscopy only if sedated.Conclusions:WIS does not ameliorate tolerance to and quality of sigmoidoscopy screening measured by several scores. When offered a choice, the women's willingness to repeat WIS or CO2S without sedation was poor and raises concern on the opportunity of screening sigmoidoscopy without sedation in these subjects.

Effects of the Colorectal Cancer Control Program.

Although colorectal cancer (CRC) screening is highly effective, screening rates lag far below recommended levels, particularly for low-income people. The Colorectal Cancer Control Program (CRCCP) funded $100 million in competitively awarded grants to 25 states from 2009-2015 to increase CRC screening rates among low-income, uninsured populations, in part by directly providing and paying for screening services. Using data from the 2001-2015 Behavioral Risk Factor Surveillance System (BRFSS) and a difference-in-differences strategy, we find no effects of CRCCP on the use of relatively cheap fecal occult blood tests (FOBT). We do, however, find that the CRCCP significantly increased the likelihood that uninsured 50-64-year-olds report ever having a relatively expensive endoscopic CRC screening (sigmoidoscopy or colonoscopy) by 2.9 percentage points, or 10.7%. These effects are larger for women, minorities, and individuals who did not undertake other types of preventive care. We do not find that the CRCCP led to significant changes in CRC cancer detection. Our results indicate that the CRCCP was effective at increasing CRC screening rates among the most vulnerable.

Validity of Case-Control Studies to Estimate Benefits from Cancer Screening

Background: Observational studies are increasingly used to estimate the effectiveness of cancer screening. However, the validity of such studies remains uncertain. Methods: 98,678 individuals were included in the Norwegian Colorectal Cancer Prevention trial, a randomized sigmoidoscopy screening trial. We used the trial data and designed case-control studies nested among individuals randomized to sigmoidoscopy and compared the results with those from intention-to-treat and per-protocol analyses to test the validity of the case-control design to estimate screening effect on colorectal cancer incidence and mortality, and all-cause mortality. We analyzed the case-control studies with the following methodologies: The logistic regression method, where we adjusted for self-selection in multivariable regression models including age, sex, comorbidity, socioeconomics and ethnicity; and the self-selection method where we adjusted for self-selection by different unscreened groups: regional - and national reference population. The trial is registered with ClinicalTrials.gov, NCT00119912. Findings: In intention-to-treat analysis of the randomized trial, sigmoidoscopy screening reduced colorectal cancer mortality by 19% (relative risk (RR) 0.81; 95% CI 0.67-0.99). When the same data were analyzed with a case-control design, the reductions varied between 44% (RR 0.56; 95% CI 0.33-0.97) and 67% (odds ratio (OR) 0.33; 95% CI 0.22-0.51) depending on the method used. While the intention-to-treat analysis showed no screening benefit on all-cause mortality (RR 1.00; 95% CI 0.97-1.03), the case-control studies suggested a benefit between 22% (RR 0.78; 95% CI 0.71-0.85) and 57% (OR 0.42; 95% CI 0.39-0.45) depending on the method used. Interpretation: Observational studies may overestimate the benefits of cancer screening and should therefore not guide screening policies. Clinical Trials: ClinicalTrials.gov, NCT00119912 Funding: The study received intramural funding from the University of Oslo and Oslo University Hospital. No external funding was provided. Declaration of Interest: None to declare. Ethical Approval: The NORCCAP trial was approved by the Ethics Committee of South-East Norway (project ID S-98052) and the Norwegian Data Protection Authority (Project ID 98/1408). The current study was approved by the NORCCAP steering committee.

Association of Screening Lower Endoscopy With Colorectal Cancer Incidence and Mortality in Adults Older Than 75 Years

Evidence indicates that screening for colorectal cancer (CRC) beginning at 50 years of age can detect early-stage CRC and premalignant neoplasms (eg, adenomas) and thus prevent CRC-related mortality. At present, the US Preventive Services Task Force recommends continuing CRC screening until 75 years of age and individualized decision-making for adults older than 75 years, while accounting for a patient's overall health and screening history. However, scant data exist to support these recommendations. To examine the association of lower gastrointestinal tract screening endoscopy with the risk of CRC incidence and CRC-related mortality in older US adults. This prospective cohort study of health care professionals in the US included data from the Nurses' Health Study (NHS) and Health Professionals Follow-up Study (HPFS) from January 1, 1988, through January 31, 2016, for the HPFS and June 30, 2016, for the NHS. Data were analyzed from May 8, 2019, to July 9, 2020. History of screening sigmoidoscopy or colonoscopy (routine/average risk or positive family history) to 75 years of age and after 75 years of age, assessed every 2 years. Incidence of CRC and CRC-related mortality confirmed by National Death Index, medical records, and pathology reports. Among 56 374 participants who reached 75 years of age during follow-up (36.8% men and 63.2% women), 661 incident CRC cases and 323 CRC-related deaths were documented. Screening endoscopy after 75 years of age was associated with reduced risk of CRC incidence (multivariable hazard ratio [HR], 0.61; 95% CI, 0.51-0.74) and CRC-related mortality (HR, 0.60; 95% CI, 0.46-0.78), regardless of screening history. The HR comparing screening with nonscreening after 75 years of age was 0.67 (95% CI, 0.50-0.89) for CRC incidence and 0.58 (95% CI, 0.38-0.87) for CRC-related mortality among participants who underwent screening endoscopy before 75 years of age, and 0.51 (95% CI, 0.37-0.70) for CRC incidence and 0.63 (95% CI, 0.43-0.93) for CRC-related mortality among participants without a screening history. However, screening endoscopy after 75 years of age was not associated with risk reduction in CRC death among participants with cardiovascular disease (HR, 1.18; 95% CI, 0.59-2.35) or significant comorbidities (HR, 1.17; 95% CI, 0.57-2.43). In this cohort study, endoscopy among individuals older than 75 years was associated with lower risk of CRC incidence and CRC-related mortality. These data support continuation of screening after 75 years of age among individuals without significant comorbidities.

Comparative Effectiveness of Fecal Immunochemical Tests versus Flexible Sigmoidoscopy for Colorectal Cancer Screening: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.

Fecal immunochemical tests (FITs) and flexible sigmoidoscopies are commonly used modalities for colorectal cancer (CRC) screening. We performed a systematic review and meta-analysis to compare the effectiveness of FIT and sigmoidoscopy in CRC screening. PRISMA statement and Cochrane guidelines were followed for this review. Digital dissertation databases were searched from inception till December 1st 2020 and randomized clinical trials comparing the detection rates of CRC for FIT and sigmoidoscopy were included. Outcomes for analysis included participation rates and detection rates of CRC, advanced adenomas and advanced colorectal neoplasia for both screening modalities. Five randomized clinical trials with a total of 261,755 patients were included for the analysis. The participation rate for FIT was significantly higher compared to flexible sigmoidoscopy (OR 2.11, 95% CI 1.29-3.44, p=0.003). In intention-to-screen analysis, the detection rate for advanced colorectal neoplasia was significantly lower with FIT (OR 0.62, 95% CI 0.45-0.84, p=0.002) as compared to flexible sigmoidoscopy but not statistically different for CRC (OR 1.15, 95% CI 0.65-2.02, p=0.63). Despite lower participation amongst patients, CRC screening with flexible sigmoidoscopy leads to higher detection of advanced colorectal neoplasia, when compared to a single round of fecal immunochemical testing.

WASh multicentre randomised controlled trial: water-assisted sigmoidoscopy in English NHS bowel scope screening

ObjectivesThe English Bowel Cancer Screening Programme invites 55 year olds for a sigmoidoscopy (Bowel Scope Screening (BSS)), aiming to resect premalignant polyps, thus reducing cancer incidence. A national patient survey...

Estimation of overdiagnosis in colorectal cancer screening with sigmoidoscopy and faecal occult blood testing: comparison of simulation models

ObjectiveTo estimate overdiagnosis of colorectal cancer (CRC) for screening with sigmoidoscopy and faecal occult blood testing (FOBT).DesignSimulation study using data from randomised trials.SettingPrimary screening, UK, NorwayParticipants152 850 individuals from the...

Effects of screening for colorectal cancer: Development, documentation and validation of a multistate Markov model

Simulation models are a powerful tool to overcome gaps of evidence needed to inform medical decision-making. Here, we present development and application of COSIMO, a Markov-based Colorectal Cancer (CRC) Multi-state Simulation Model to simulate effects of CRC screening, along with a thorough assessment of the model's ability to reproduce real-life outcomes. Firstly, we provide a comprehensive documentation of COSIMO's development, structure and assumptions. Secondly, to assess the model's external validity, we compared model-derived cumulative incidence and prevalences of colorectal neoplasms to (a) results from KolosSal, a study in German screening colonoscopy participants, (b) registry-based estimates of CRC incidence in Germany, and (c) outcome patterns of randomized sigmoidoscopy screening studies. We found that (a) more than 90% of observed prevalences in the KolosSal study were within the 95% confidence intervals of the model-predicted neoplasm prevalences; (b) the 15-year cumulative CRC incidences estimated by simulations for the German population deviated by 0.0% to 0.2% units in men and 0.0% to 0.3% units in women when compared to corresponding registry-derived estimates; and (c) the time course of cumulative CRC incidence and mortality in the modeled intervention group and control group closely resembles the time course reported from sigmoidoscopy screening trials. Overall, COSIMO adequately predicted colorectal neoplasm prevalences and incidences in a German population for up to 25 years, with estimated patterns of the effect of screening colonoscopy resembling those seen in registry data and real-world studies. This suggests that the model may represent a valid tool to assess the comparative effectiveness of CRC screening strategies.